Azimuthal structures of ray auroras at the beginning of auroral substorms
|
|
- Tiffany Phillips
- 5 years ago
- Views:
Transcription
1 GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L23106, doi: /2009gl041252, 2009 Azimuthal structures of ray auroras at the beginning of auroral substorms K. Sakaguchi, 1 K. Shiokawa, 1 and E. Donovan 2 Received 5 October 2009; revised 11 November 2009; accepted 18 November 2009; published 12 December [1] The time evolution of optical structures in brightening auroras was examined for two substorm events that occurred on January 15, 2008 and February 27, The onsets of both auroral substorms were captured in the field of view of an all-sky TV camera at Gillam, Canada. We found that in both cases, the brightening auroras formed vertical structures, or so-called ray auroras, which lined up longitudinally for several tens of seconds before luminosity increased sharply. The ray structure implies precipitating electrons accelerated over a broad energy range at substorm onset. Two dimensional Fourier transform analysis of the auroral images showed the ray auroras have characteristic wavenumbers and harmonics that develop within a few seconds of the initial brightening. These results suggest that dispersive Alfvén waves containing turbulent parallel electric fields form in brightening regions at the beginning of auroral substorms. Citation: Sakaguchi, K., K. Shiokawa, and E. Donovan (2009), Azimuthal structures of ray auroras at the beginning of auroral substorms, Geophys. Res. Lett., 36, L23106, doi: /2009gl Introduction [2] Auroras at substorm onset become active and their luminosity rapidly increases in a fraction of a second. Recent high time resolution imaging has shown that brightening region expands rapidly westward/eastward along the onset arc at a speed that starts at about 20 km/s, and the speed exponentially decreases over time [Sakaguchi et al., 2009]. During such rapid longitudinal expansion, brightening auroras feature wave-like (in longitude) formations with wavelengths of km [Donovan et al., 2006; Liang et al., 2008; Rae et al., 2009]. It is thought that the intensification process of upward field-aligned currents in the plasma sheet and/or generation of parallel electric fields at high altitudes that accelerate auroral electrons are mapped to the brightening auroral forms at substorm onset. [3] The purpose of this study is to focus on the initial (tens of seconds) spatio-temporal evolutions of the optical structures observed in the brightening auroras, by using video-rate imaging data obtained from the ground. The likelihood of observing a substorm aurora from its initial brightening is low, and obtaining imaging data of it with a high sampling rate is even more difficult. However, in order to examine the brightening dynamics on the time scale of 1 Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Japan. 2 Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada. Copyright 2009 by the American Geophysical Union /09/2009GL seconds, time resolutions of less than a second are necessary. The characteristic spatio-temporal scales of a brightening aurora are expected to be observable in this initial interval before other onset-related processes affect the aurora. These characteristic scales may constrain theories describing the acceleration mechanisms of auroral electrons [Borovsky, 1993] and/or the possible plasma instabilities that trigger the substorm onset [Lui, 2004]. 2. Observations [4] In this study we used auroral data obtained by an allsky TV camera during the THEMIS-ground campaign at Gillam (geographic latitude 56.4 N, geographic longitude E, dipole geomagnetic latitude 65.6 ), Canada. This all-sky TV camera observes white-light auroral images at a sampling rate of frames/s. A detailed description of the campaign observations and instrumentation has been reported by Shiokawa et al. [1996, 2009]. [5] The events presented herein were observed at the beginning of auroral intensifications that developed into substorms within the field of view of the Gillam all-sky TV camera on January 15, 2008 and February 27, An eastwest keogram of the first event was shown by Sakaguchi et al. [2009]. Figure 1 shows the x-component magnetic field recorded at the auroral onset site of Gillam (GILL) with a magnetometer in the CARISMA array [Mann et al., 2008] and the x-component magnetic field fluctuations recorded by UCLA magnetometers [Russell et al., 2008] at mid-latitude sites at Pine Ridge (PINE) and Hot Springs (HOTS). The magnetic fluctuations are filtered for Pi2 frequency range (period: s). Onset times defined as the moment of brightening identified at Gillam are indicated by dashed lines. Figure 1 shows that two typical magnetic-field signatures during substorms become remarkable after the optical onsets. The first is the Pi2 geomagnetic pulsations at mid-latitudes. The second is the decrease of the x-component magnetic field in the auroral zone. The maximum amplitudes of magneticfield depressions were approximately 150 nt for the January 15, 2008 event and 50 nt for the February 27, 2009 event. 3. Fourier Analysis [6] In order to investigate the optical structures and their evolution in brightening auroras at substorm onset, auroral images were analyzed using a two-dimensional Fourier transform method. Figures 2 (middle) and 3(middle) show time sequences of the auroral intensifications at intervals of 3 and 5 s, respectively. The vertical (geographic northsouth) and horizontal (geographic east-west) dimensions of the images are given in kilometers, assuming an emission L of5
2 Figure 1. (a, c) X-component magnetic fields observed at onset site and (b, d) fluctuations of x-component magnetic field in the Pi2 range observed at mid-latitude site on January 15, 2008 and February 27, Dashed lines indicate onset times of auroral intensification. altitude of 100 km, and magnetic zenith is indicated by the asterisk. For both events brightening auroras have wavelike structures and appear to radiate from the magnetic zenith. Such auroral structures are called ray auroras. Figures 2 (bottom) and 3 (bottom) show power spectral densities in the wavenumber domain obtained by the Fourier method using the auroral images shown in Figures 2 (middle) and 3 (middle). Hanning windows were applied to each auroral image before the Fourier transform. The vertical and horizontal dimensions indicate the number of sinusoidal waves in 256-km segments in directions of geographic latitude and longitude, respectively. [7] Strong spectral peaks are visible at the center of all wavenumber domain images in Figures 2 and 3. In addition, vertically aligned second-, third-, and higher-order spectral peaks are clearly visible in the wavenumber images except for plot a for both events (Figures 2 and 3). These vertically aligned peaks indicate small-scale longitudinal structures in the brightening auroras. The third- and higher-order spectral peaks have wavenumbers in multiples of the second-order spectral peak in each image, indicating harmonic structures. These harmonic structures correspond to new auroral rays that appear between the pre-existing auroral rays shown in Figures 2 (middle) and 3 (middle). [8] Figures 2 (top) and 3 (top) show high-resolution dynamic spectra of wavenumber (corresponding wavelengths are shown on the right axis) in the geographic longitudinal direction. One spectral line was obtained from the first and second quadrants of the wavenumber domain image in Figures 2 (bottom) and 3 (bottom), in which all latitudinal components were integrated. Figures 2 (top) and 3 (top) show the time variations of the spectral peak of wavenumber during a 60-s period. The times of Figures 2 (middle), 2 (bottom), 3 (middle), and 3 (bottom) are indicated by dashed lines in the dynamic spectra. [9] In the case of the January 15, 2008 event (Figure 2), the wavenumber spectrum has several discrete peaks at the beginning of auroral intensification at 04:55:40 04:55:48 UT. Figure 2. Brightening auroral images and wavenumber spectra at the beginning of a substorm on January 15, (top) Dynamic spectra of wavenumeber/wavelength (left/right axis) in the east-west direction at 04:55:30 04:56:30 UT, (middle) white-light auroral images every 3 s, and (bottom) power spectral densities in wavenumber domain of Figure 2 (middle) obtained by Fourier translation. A yellow asterisk in Figure 2 (middle) indicates the location of the magnetic zenith. 2of5
3 Figure 3. Brightening auroral images and wavenumber spectra at the beginning of a substorm on February 27, (top) Dynamic spectra of wavenumeber/wavelength (left/right axis) in the east-west direction at 05:26:30 05:27:30 UT, (middle) white-light auroral images every 3 s, and (bottom) power spectral densities in wavenumber domain of Figure 2 (middle) obtained by Fourier translation. A yellow asterisk in Figure 2 (middle) indicates the location of the magnetic zenith. The wavenumbers (wavelengths) of the spectral peaks are 3.5 (73 km) and 7 (36 km). The harmonic 36-km structure appears a few seconds after the appearance of the 73-km structure, however, these structures last only a few seconds. The wavenumbers of these spectral peaks decrease gradually. Decreasing wavenumbers indicated by the downward-sloping trend, is a general feature on this dynamic spectrum. [10] In the case of the February 27, 2009 event (Figure 3), the wavenumber spectrum also has clear discrete peaks during auroral intensification after 05:26:42 UT. The spectral peaks are located at wavenumbers (wavelengths) of 6(43 km) and 11 (23 km). Here, we also find a trend of decreasing wavenumbers similar to that seen for the first event (Figure 2). The wavelength (43 km) of the initial structures stayed more or less constant for about 10 seconds, and then subsequently increased (decreasing wavenumber). 4. Discussion and Summary [11] We identified commonly observed optical structures that are characteristic of brightening auroras for two isolated substorm onsets. Herein, the onset denotes the time of initial enhancement of auroral luminosity with fast longitudinal development before major poleward expansion. Time variations of auroral luminosities integrated over an area of km 2 are shown in Figure 4. The line plots of both events have two kinks, The kinks indicating that the substorm auroras intensified through two phases, gradually at first and rapidly later. The characteristic spectra seen in Figures 2 and 3 were observed during the initial gradual phase of auroral intensification. [12] The time sequences of auroral images for both events show that from pre-existing weak auroral arcs, onset aurora appeared as rays emitted from the magnetic zenith. It is noteworthy that filtered auroral intensities observed by the meridian scanning photometer ( ca/norstar/). The data show that proton (H b ) auroras are on the equatorward of the pre-existing weak auroral arcs, indicating that the ray auroras mapped to the central plasma sheet. Since the stopping heights of precipitating electrons in the ionosphere are determined by electron energies, the vertical depth of the excitation segment of auroral particles becomes wider as the energy spectrum of electrons becomes broader [e.g., Rees, 1963], so the ray auroras are almost certainly the result of the precipitation of electrons with Figure 4. Auroral luminosities observed on (a) January 15, 2008 and (b) February 27, 2009, integrated over an area of km 2 corresponding to image size of Figures 2 (middle) and 3 (middle). 3of5
4 broadband energy spectra. Recent particle observations of auroral electrons at initial brightening have demonstrated that auroras surging poleward were dominated by a burst of superthermal electrons with a field-aligned pitch angle distribution [Mende et al., 2003]. In addition, Mende et al. [2003] confirmed signatures of dispersive Alfvén waves with superthermal electrons from the pitch-angle distribution of ions and magnetometer measurements. The dispersive Alfvén waves carry the turbulent electric field parallel to the geomagnetic field and are able to accelerate electrons to superthermal energies [Chaston et al., 2000]. For the event investigated by Mende et al. [2003], a detailed structure of the aurora that was probably produced by superthermal electrons was not observed since they used global auroral images obtained by the IMAGE satellite. However, we speculate that ray auroras can be caused by precipitation of superthermal electrons since under the Alvénic accelerations electrons have multiple energy fluxes with small wavelengths transverse to magnetic fields. [13] Ground-based multi-spectral observations of auroras by Deehr and Lummerzheim [2001] have consistently shown a different aspect of the above scenario of Alfvénic electron precipitation into onset auroras. They reported enhancement of the 630-nm emission in the onset arc relative to other emissions just prior to onset, indicating an increase of electron number flux with average energies less than 100 ev. These observations of the broadband energy spectrum of auroral electrons at substorm onset agree with the expected electron energy spectrum from our observations of ray auroras at the time of initial brightening. Thus, the auroral ray structures, which can be formed under Alfvénic accelerations at the substorm onset, indicate incoming bursty Alfvén waves prior to the expansion phase of the auroral substorm. [14] The ray auroras observed at substorm onset were aligned longitudinally. The number of visible rays in the longitudinal segment became denser after a few seconds due to appearance of smaller rays in between. The results of two-dimensional Fourier transforms applied to the auroral images showed that wavenumber spectra contained several peaks after initial brightening. These wavenumbers were found to be harmonics of the fundamental mode. Dynamic spectra showing time variations of longitudinal wavelengths demonstrated that harmonic wavenumbers appeared after a few seconds. In other words, the brightening aurora immediately cascaded into smaller structures after a few seconds. Similar dynamics of dispersive Alfvén wave propagation in the ionospheric Alfvén resonator (IAR) have been observed in the simulations by Lysak and Song [2008]. In their simulation, the scaling transition of Alfvén waves occurred after a few seconds when the reflected wave from the ionosphere first interfered with the incident waves. Then, the perpendicular structure of Poynting fluxes decayed to half and half in the density cavities. The time delay of wave interference in the IAR is consistent with the time scale (a few seconds) of the appearance of harmonic wavenumbers in ray auroras for the present events. Generation of harmonic structures in the brightening auroras was repeatedly observed in dynamic spectra, especially in Figure 3. The lifetime of these fine structures ranged from a few seconds to ten seconds. This is consistent with the expected lifetime of parallel electric fields carried by dispersive Alfvén waves with no time variation [Stasiewicz et al., 2000]. [15] The findings obtained from the observations of substorm onsets presented in this paper are summarized as follows. [16] 1. Auroral brightening arises from ray auroras that have characteristic wavenumbers in the longitudinal direction; in the present cases, the wavelengths were 73 km and 43 km, respectively. [17] 2. The distance between rays becomes shorter due to the growth of new small rays; several harmonics were observed in the wavenumber domain spectra. [18] 3. Small-scale structures last less than 10 s and gradually become larger structures. [19] These structures and the time variations observed for brightening auroras suggest that dispersive Alfvén waves are present along the field line above the brightening aurora. In future studies, we plan to investigate the origin of these Alfvén waves, specifically, where and how they are launched with characteristic azimuthal structures. [20] Acknowledgments. The auroral campaign observations at Gillam were carried out by the Solar-Terrestrial Environment Laboratory, Nagoya University in collaboration with the Canadian Space Agency (CSA), and with the support from the University of Calgary NORSTAR team. We acknowledge S. Mende, C. T. Russell, and I. R. Mann for the use of GMAG data, CARISMA is operated and deployed by the University of Alberta, and funded by the CSA. This work was supported by a Grant-in-Aid for Scientific Research ( ) and Special Funds for Education and Research (Energy Transport Processes in Geospace) from MEXT, Japan and JSPS Research Fellowships for Young Scientists. References Borovsky, J. (1993), Auroral arc thicknesses as predicted by various theories, J. Geophys. Res., 98, Chaston, C. C., C. W. Carlson, R. E. Ergun, and J. P. McFadden (2000), Alfvén waves, density cavities and electron acceleration observed from the FAST spacecraft, Phys. Scr. T, 84, Deehr, C., and D. Lummerzheim (2001), Ground-based optical observations of hydrogen emission in the auroral substorm, J. Geophys. Res., 106, Donovan, E., S. B. Mende, B. Jackel, M. Syrjäsuo, M. Meurant, I. Voronkov, H. U. Frey, V. Angelopoulos, and M. Connors (2006), The azimuthal evolution of the substorm expansive phase onset aurora, in Proceedings of the Eighth International Conference on Substorms, edited by M. Syrjäsuo and E. Donovan, pp , Univ. of Calgary, Calgary, Alberta, Canada. Liang, J., E. F. Donovan, W. W. Liu, B. Jackel, M. Syrjäsuo, S. B. Mende, H. U. Frey, V. Angelopoulos, and M. Connors (2008), Intensification of preexisting auroral arc at substorm expansion phase onset: Wave-like disruption during the first tens of seconds, Geophys. Res. Lett., 35, L17S19, doi: /2008gl Lui, A. T. Y. (2004), Potential plasma instabilities for substorm expansion onsets, Space. Sci. Rev., 113, Lysak, R. L., and Y. Song (2008), Propagation of kinetic Alfvén waves in the ionospheric Alfvén resonator in the presence of density cavities, Geophys. Res. Lett., 35, L20101, doi: /2008gl Mann, I. R., et al. (2008), The upgraded CARISMA magnetometer array in the THEMIS era, Space Sci. Rev., 141, , doi: /s Mende, S. B., C. W. Carlson, H. U. Frey, L. M. Peticolas, and N. Østgaard (2003), FAST and IMAGE-FUV observations of a substorm onset, J. Geophys. Res., 108(A9), 1344, doi: /2002ja Rae, I. J., et al. (2009), Timing and localization of ionospheric signatures associated with substorm expansion phase onset, J. Geophys. Res., 114, A00C09, doi: /2008ja Rees, M. H. (1963), Auroral ionization and excitation by incident energetic electrons, Planet. Space Sci., 11, Russell, C. T., P. J. Chi, D. J. Dearborn, Y. S. Ge, B. Kuo-Tiong, J. D. Means, D. R. Pierce, K. M. Rowe, and R. C. Snare (2008), THEMIS ground-based magnetometers, Space Sci. Rev., 141, , doi: /s of5
5 Sakaguchi, K., K. Shiokawa, A. Ieda, R. Nomura, A. Nakajima, M. Greffen, E. Donovan, I. R. Mann, H. Kim, and M. Lessard (2009), Fine structures and dynamics in auroral initial brightening at substorm onsets, Ann. Geophys., 27, Shiokawa, K., et al. (1996), Auroral observations using automatic optical instruments: Relations with multiple Pi 2 magnetic pulsations, J. Geomagn. Geoelectr., 48, Shiokawa, K., et al. (2009), Longitudinal development of a substorm brightening arc, Ann. Geophys., 27, Stasiewicz, K., et al. (2000), Small scale Alfvénic structure in the aurora, Space Sci. Rev., 92, E. Donovan, Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4, Canada. K. Sakaguchi and K. Shiokawa, Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi , Japan. (kaori@stelab.nagoya-u.ac.jp) 5of5
Longitudinal development of a substorm brightening arc
Ann. Geophys., 27, 1935 19, 29 www.ann-geophys.net/27/1935/29/ Author(s) 29. This work is distributed under the Creative Commons Attribution 3. License. Annales Geophysicae Longitudinal development of
More informationRelationship of Oscillating Aurora to Substorms and Magnetic Field Line Resonances
Proceedings ICS-6, 2002 Relationship of Oscillating Aurora to Substorms and Magnetic Field Line Resonances James A. Wanliss and Robert Rankin Department of Physics, University of Alberta Edmonton, AB,
More informationSimultaneous THEMIS in situ and auroral observations of a small substorm
Simultaneous THEMIS in situ and auroral observations of a small substorm E. Donovan (1), W. Liu (2), J. Liang (2), E. Spanswick (1), I. Voronkov (3), M. Connors (3), M. Syrjäsuo (4), G. Baker (1), B. Jackel
More informationRelation of substorm breakup arc to other growth-phase auroral arcs
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A11, 1390, doi:10.1029/2002ja009317, 2002 Relation of substorm breakup arc to other growth-phase auroral arcs L. R. Lyons, 1 I. O. Voronkov, 2 E. F. Donovan,
More informationRelation of Substorm Breakup Arc to other Growth-Phase Auroral Arcs
Relation of Substorm Breakup Arc to other Growth-Phase Auroral Arcs by L. R. Lyons Department of Atmospheric Sciences University of California, Los Angeles Los Angeles, CA 90095-1565 I. O. Voronkov Dept.
More informationPolarization of Pc1/EMIC waves and related proton auroras observed at subauroral latitudes
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117,, doi:10.1029/2011ja017241, 2012 Polarization of Pc1/EMIC waves and related proton auroras observed at subauroral latitudes R. Nomura, 1 K. Shiokawa, 1 K. Sakaguchi,
More informationSimultaneous THEMIS in situ and auroral observations of a small substorm
Click Here for Full Article GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L17S18, doi:10.1029/2008gl033794, 2008 Simultaneous THEMIS in situ and auroral observations of a small substorm E. Donovan, 1 W. Liu,
More informationVisualization of ion cyclotron wave and particle interactions in the inner magnetosphere via THEMIS-ASI observations
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117,, doi:10.1029/2012ja018180, 2012 Visualization of ion cyclotron wave and particle interactions in the inner magnetosphere via THEMIS-ASI observations K. Sakaguchi,
More informationTwo-dimensional structure of auroral poleward boundary intensifications
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A11, 1350, doi:10.1029/2001ja000260, 2002 Two-dimensional structure of auroral poleward boundary intensifications E. Zesta, 1 E. Donovan, 2 L. Lyons, 1 G.
More informationRelations between multiple auroral streamers, pre onset thin arc formation, and substorm auroral onset
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116,, doi:10.1029/2011ja016768, 2011 Relations between multiple auroral streamers, pre onset thin arc formation, and substorm auroral onset Y. Nishimura, 1,2 L. R.
More information1) Dept. Earth Planet. Sci., Kyushu Univ., 2) AOS, UCLA, 3) ICSWSE, Kyushu Univ., 4) APL, Johns Hopkins Univ., 5) NICT, 6) EPSS/IGPP, UCLA
IUGONET 2016/10/18-19 PBI Pi2 1), 2), 1)3), 3), Shinichi Ohtani 4), 5), V. Angelopoulos 6) 1) Dept. Earth Planet. Sci., Kyushu Univ., 2) AOS, UCLA, 3) ICSWSE, Kyushu Univ., 4) APL, Johns Hopkins Univ.,
More informationSubstorms: Externally Driven Transition to Unstable State a few Minutes Before Onset
Substorms: Externally Driven Transition to Unstable State a few Minutes Before Onset L. R. Lyons 1, I. O Voronkov 2, J. M. Ruohoniemi 3, E. F. Donovan 4 1 Department of Atmospheric Sciences, University
More informationNonlinear stability of the near-earth plasma sheet during substorms
9 Nonlinear stability of the near-earth plasma sheet during substorms P. Dobias, J. A. Wanliss, and J. C. Samson 1. Introduction Abstract: We analyze a nonlinear stability of the near-earth plasma sheet
More informationPlanned talk schedule. Substorm models. Reading: Chapter 9 - SW-Magnetospheric Coupling from Russell book (posted)
Reading: Chapter 9 - SW-Magnetospheric Coupling from Russell book (posted) Today: Example of dynamics/time variation Review of intro to auroral substorms Substorm models How do we know a substorm is occurring?
More information12. Low Latitude A.urorae on October 21, I
No. 3] Proc. Japan Acad., 66, Ser. B (199) 47 12. Low Latitude A.urorae on October 21, 1989. I By Hiroshi MIYAOKA, *) Takeo HIRASAWA, *) Kiyohumi and Yoshihito TANAKA**> (Communicated by Takesi NAGATA,
More informationNear Earth initiation of a terrestrial substorm
Near Earth initiation of a terrestrial substorm Article Published Version Rae, I. J., Mann, I. R., Angelopoulos, V., Murphy, K. R., Milling, D. K., Kale, A., Frey, H. U., Rostoker, G., Russell, C. T.,
More informationMultipoint observations of substorm pre-onset flows and time sequence in the ionosphere and magnetosphere
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117,, doi:10.1029/2011ja017185, 2012 Multipoint observations of substorm pre-onset flows and time sequence in the ionosphere and magnetosphere Yong Shi, 1 Eftyhia
More informationAuroral Disturbances During the January 10, 1997 Magnetic Storm
Auroral Disturbances During the January 10, 1997 Magnetic Storm L. R. Lyons and E. Zesta J. C. Samson G. D. Reeves Department of Atmospheric Sciences Department of Physics NIS-2 Mail Stop D436 University
More informationConvection dynamics and driving mechanism of a small substorm during dominantly IMF By+, Bz+ conditions
GEOPHYSICAL RESEARCH LETTERS, VOL. 31, L08803, doi:10.1029/2003gl018878, 2004 Convection dynamics and driving mechanism of a small substorm during dominantly IMF By+, Bz+ conditions Jun Liang, 1 G. J.
More informationTokyo Institute of Technology Ookayama , Meguro Tokyo , Japan Yoshinodai, Sagamihara Kanagawa , Japan
Structured Currents Associated with Tail Bursty Flows During Turbulent Plasma Sheet Conditions by L. R. Lyons1, T. Nagai2, J. C. Samson3, E. Zesta1, T. Yamamoto4, T, Mukai4, A. Nishida4,, S. Kokubun5 1Department
More informationThe Two-Dimensional Structure of Auroral Poleward Boundary Intensifications (PBI)
The Two-Dimensional Structure of Auroral Poleward Boundary Intensifications (PBI) E. Zesta 1, E. Donovan 2, L. Lyons 1, G. Enno 2, J. S. Murphree 2, and L. Cogger 2 1 Department of Atmospheric Sciences,
More informationProperties of small-scale Alfvén waves and accelerated electrons from FAST
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. A4, 8003, doi:10.1029/2002ja009420, 2003 Properties of small-scale Alfvén waves and accelerated electrons from FAST C. C. Chaston, J. W. Bonnell, C. W. Carlson,
More informationOptical characterization of the growth and spatial structure of a substorm onset arc
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2010ja015376, 2010 Optical characterization of the growth and spatial structure of a substorm onset arc I. J. Rae, 1 C. E. J. Watt, 1 I. R. Mann,
More informationObserving and analysing structures in active aurora with the ASK optical instrument and EISCAT radar.
1 (25) Motivating talk on exciting work with EISCAT: Observing and analysing structures in active aurora with the ASK optical instrument and EISCAT radar. EISCAT Summer School part I - 31 st July 2007
More informationSimultaneous DMSP, all-sky camera, and IMAGE FUV observations of the brightening arc at a substorm pseudo-breakup
Earth Planets Space, 59, 5 9, 007 Simultaneous DMSP, all-sky camera, and IMAGE FUV observations of the brightening arc at a substorm pseudo-breakup K. Yago 1,5, K. Shiokawa 1, K. Yumoto, D. G. Baishev,
More informationNear-Earth Breakup in Substorms: Empirical and Model Constraints
Near-Earth Breakup in Substorms: Empirical and Model Constraints I. O. Voronkov 1, E. F. Donovan, P. Dobias 1, J. C. Samson 1, and L. R. Lyons 3 1 Department of Physics, University of Alberta Edmonton,
More informationOn the nature of ULF wave power during nightside auroral activations and substorms: 2. temporal evolution
On the nature of ULF wave power during nightside auroral activations and substorms: 2. temporal evolution Article Published Version Rae, I. J., Murphy, K. R., Watt, C. E. J. and Mann, I. R. (2011) On the
More informationTail Reconnection Triggering Substorm Onset
Tail Reconnection Triggering Substorm Onset Vassilis Angelopoulos 1, James P. McFadden, Davin Larson, Charles W. Carlson, Stephen B. Mende, Harald Frey, Tai Phan, David G. Sibeck, Karl-Heinz Glassmeier,
More informationTime Series of Images of the Auroral Substorm
ESS 7 Lecture 13 October 27, 2010 Substorms Time Series of Images of the Auroral Substorm This set of images in the ultra-violet from the Polar satellite shows changes that occur during an auroral substorm.
More informationLongitudinally propagating arc wave in the pre-onset optical aurora
Click Here for Full Article GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L21103, doi:10.1029/2009gl040777, 2009 Longitudinally propagating arc wave in the pre-onset optical aurora V. M. Uritsky, 1 J. Liang,
More informationOvercoming Uncertainties in the Relation between Source and Aurora
Unsolved Problems in Magnetospheric Physics Scarborough, UK, 06-12 September 2015 Overcoming Uncertainties in the Relation between Source and Aurora Gerhard Haerendel Max Planck Institute for Extraterrestrial
More informationAndrew Keen, Inari, Finland 18 Feb º C spaceweather.com
ESS 7 Lecture 17 May 14, 2010 The Aurora Aurora Amazing Light Show Andrew Keen, Inari, Finland 18 Feb 2010-31º C spaceweather.com Athabasca Aurora Oct 3 2003 Courtesy Mikko Syrjäsuo There is a Long Record
More informationJournalofGeophysicalResearch: SpacePhysics
JournalofGeophysicalResearch: SpacePhysics RESEARCH ARTICLE Key Points: We present two examples of auroral fragmentation in all-sky auroral images The auroral fragmentation is probably caused by pressure-driven
More informationTHEMIS observations of consecutive bursts of Pi2 pulsations: The 20 April 2007 event
Click Here for Full Article JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114,, doi:10.1029/2008ja013538, 2009 THEMIS observations of consecutive bursts of Pi2 pulsations: The 20 April 2007 event C.-C. Cheng,
More informationSimultaneous ground and satellite observations of an isolated proton arc at subauroral latitudes
JOURNAL OF GEOPHYSICAL RESEARCH, VOL.???, XXXX, DOI:.29/, Simultaneous ground and satellite observations of an isolated proton arc at subauroral latitudes Sakaguchi, K., K. Shiokawa, A. Ieda, Y. Miyoshi,
More informationStepwise feature of aurora during substorm expansion compared with the near Earth tail dipolarization: Possible types of substorm dynamics
Click Here for Full Article JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2009ja014572, 2010 Stepwise feature of aurora during substorm expansion compared with the near Earth tail dipolarization:
More informationTail Reconnection Triggering Substorm Onset
Tail Reconnection Triggering Substorm Onset Vassilis Angelopoulos, 1* James P. McFadden, 2 Davin Larson, 2 Charles W. Carlson, 2 Stephen B. Mende, 2 Harald Frey, 2 Tai Phan, 2 David G. Sibeck, 3 Karl-Heinz
More informationSmall-Scale Structure of Ionospheric Absorption of Cosmic Noise During Pre-Onset and Sharp Onset Phases of an Auroral Absorption Substorm
Geophysica (1999), 35(1-2), 45-57 Small-Scale Structure of Ionospheric Absorption of Cosmic Noise During Pre-Onset and Sharp Onset Phases of an Auroral Absorption Substorm Hilkka Ranta 1, Aarne Ranta 1
More informationSimultaneous ground and satellite observations of an isolated proton arc at subauroral latitudes
Click Here for Full Article JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112,, doi:10.1029/2006ja012135, 2007 Simultaneous ground and satellite observations of an isolated proton arc at subauroral latitudes K.
More informationEvolution in space and time of the quasi static acceleration potential of inverted V aurora and its interaction with Alfvénic boundary processes
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116,, doi:10.1029/2011ja016537, 2011 Evolution in space and time of the quasi static acceleration potential of inverted V aurora and its interaction with Alfvénic
More informationFeatures of magnetosphere-ionosphere coupling during breakups and substorm onsets inferred from multi-instrument alignment
Features of magnetosphere-ionosphere coupling during breakups and substorm onsets inferred from multi-instrument alignment I. Voronkov, A. Runov, A. Koustov, K. Kabin, M. Meurant, E. Donovan, C. Bryant,
More informationIn-Situ vs. Remote Sensing
In-Situ vs. Remote Sensing J. L. Burch Southwest Research Institute San Antonio, TX USA Forum on the Future of Magnetospheric Research International Space Science Institute Bern, Switzerland March 24-25,
More informationGround based observations of diffuse auroral frequencies in the context of whistler mode chorus
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2009ja014852, 2010 Ground based observations of diffuse auroral frequencies in the context of whistler mode chorus M. Samara 1 and R. G. Michell
More informationPlasma pressure generated auroral current system: A case study
GEOPHYSICAL RESEARCH LETTERS, VOL. 39,, doi:10.1029/2012gl051211, 2012 Plasma pressure generated auroral current system: A case study S. B. Mende, 1 S. L. England, 1 and H. U. Frey 1 Received 2 February
More informationSmall Scale Structures and Motions of Auroral Signatures as Observed From the Ground: a Planned Field Study Using Camera and Radar Observations
Small Scale Structures and Motions of Auroral Signatures as Observed From the Ground: a Planned Field Study Using Camera and Radar Observations Preliminary Results for Return Current Region Structures
More informationGlobal MHD Eigenmodes of the Outer Magnetosphere
Global MHD Eigenmodes of the Outer Magnetosphere Andrew Wright UNIVERSITY OF ST ANDREWS Magnetospheric Structure: Cavities and Waveguides The Earth s magnetosphere is structured by magnetic fields and
More informationRevised timing and onset location of two isolated substorms observed by Time History of Events and Macroscale Interactions During Substorms (THEMIS)
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116,, doi:10.1029/2010ja015877, 2011 Revised timing and onset location of two isolated substorms observed by Time History of Events and Macroscale Interactions During
More informationMagnetospheric field-line resonances: Ground-based observations and modeling
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110,, doi:10.1029/2004ja010919, 2005 Magnetospheric field-line resonances: Ground-based observations and modeling R. Rankin, K. Kabin, J. Y. Lu, I. R. Mann, R. Marchand,
More informationJoule heating and nitric oxide in the thermosphere, 2
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2010ja015565, 2010 Joule heating and nitric oxide in the thermosphere, 2 Charles A. Barth 1 Received 14 April 2010; revised 24 June 2010; accepted
More informationWave-particle interactions in dispersive shear Alfvèn waves
Wave-particle interactions in dispersive shear Alfvèn waves R. Rankin and C. E. J. Watt Department of Physics, University of Alberta, Edmonton, Canada. Outline Auroral electron acceleration in short parallel
More informationEnhanced transport across entire length of plasma sheet boundary field lines leading to substorm onset
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2010ja015831, 2010 Enhanced transport across entire length of plasma sheet boundary field lines leading to substorm onset L. R. Lyons, 1 Y. Nishimura,
More informationGround and satellite observations of substorm onset arcs
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110,, doi:10.1029/2005ja011281, 2005 Ground and satellite observations of substorm onset arcs K. Shiokawa, 1 K. Yago, 1,2 K. Yumoto, 3 D. G. Baishev, 4 S. I. Solovyev,
More informationDetailed analysis of a substorm event on 6 and 7 June 1989: 2. Stepwise auroral bulge evolution during expansion phase
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 107, NO. A12, 1480, doi:10.1029/2001ja009129, 2002 Detailed analysis of a substorm event on 6 and 7 June 1989: 2. Stepwise auroral bulge evolution during expansion
More informationLuminosity variations in several parallel auroral arcs before auroral breakup
Ann. Geophysicae 15, 959±966 (1997) Ó EGS ± Springer-Verlag 1997 Luminosity variations in several parallel auroral arcs before auroral breakup V. Safargaleev, W. Lyatsky, V. Tagirov Polar Geophysical Institute,
More informationSubstorm onset observations by IMAGE-FUV
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109,, doi:10.1029/2004ja010607, 2004 Substorm onset observations by IMAGE-FUV H. U. Frey, S. B. Mende, and V. Angelopoulos Space Sciences Laboratory, University of
More informationPreonset time sequence of auroral substorms: Coordinated observations by all sky imagers, satellites, and radars
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2010ja015832, 2010 Preonset time sequence of auroral substorms: Coordinated observations by all sky imagers, satellites, and radars Y. Nishimura,
More informationRelation of substorm disturbances triggered by abrupt solar-wind changes to physics of plasma sheet transport
1 Relation of substorm disturbances triggered by abrupt solar-wind changes to physics of plasma sheet transport L. R. Lyons, D.-Y. Lee, C.-P. Wang, and S. B. Mende 1. Introduction Abstract: Substorm onset
More informationG. Balasis (1), I. A. Daglis (1,2), M. Georgiou (1,2), C. Papadimitriou (1,2), E. Zesta (3), I. Mann (4) and R. Haagmans (5)
G. Balasis (1), I. A. Daglis (1,2), M. Georgiou (1,2), C. Papadimitriou (1,2), E. Zesta (3), I. Mann (4) and R. Haagmans (5) (1) IAASARS-National Observatory of Athens; (2) University of Athens; (3) NASA;
More informationG R O U P R E S E A R C H E R S
SW C O L L A B O R A T I O N J U P I T E R E A R T H G R O U P R E S E A R C H E R S Suwicha Wannawichian Tatphicha Promfu Paparin Jamlongkul Kamolporn Haewsantati 2 SW C O L L A B O R A T I O N C o l
More informationElectron trapping and charge transport by large amplitude whistlers
GEOPHYSICAL RESEARCH LETTERS, VOL. 37,, doi:10.1029/2010gl044845, 2010 Electron trapping and charge transport by large amplitude whistlers P. J. Kellogg, 1 C. A. Cattell, 1 K. Goetz, 1 S. J. Monson, 1
More informationExcitation of the third harmonic mode in meridian planes for Pi2 in the auroral zone
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 117,, doi:10.1029/2012ja018003, 2012 Excitation of the third harmonic mode in meridian planes for Pi2 in the auroral zone O. Saka, 1 K. Hayashi, 2,3 and D. Koga 4
More informationEstimating the peak auroral emission altitude from all-sky images
ÓPTICA PURA Y APLICADA. www.sedoptica.es Sección Especial: 37 th AMASOM / Special Section: 37 th AMASOM Aurora Estimating the peak auroral emission altitude from all-sky images L. Sangalli (1,*), B. Gustavsson
More informationGlobal morphology of substorm growth phases observed by the IMAGE-SI12 imager
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112,, doi:10.1029/2007ja012329, 2007 Global morphology of substorm growth phases observed by the IMAGE-SI12 imager V. Coumans, 1 C. Blockx, 1 J.-C. Gérard, 1 B. Hubert,
More informationESS 200C Aurorae. Lecture 15
ESS 200C Aurorae Lecture 15 The record of auroral observations dates back thousands of years to Greek and Chinese documents. The name aurora borealis (latin for northern dawn) was coined in 1621 by P.
More informationSubstorm onset dynamics in the magnetotail as derived from joint TC-1 and Cluster data analysis
Earth Planets Space, 60, 613 621, 2008 Substorm onset dynamics in the magnetotail as derived from joint TC-1 and Cluster data analysis H. Wang 1,3,H.Lühr 2,S.Y.Ma 1, and A. J. Ridley 3 1 College of Electronic
More informationObservations of the phases of the substorm
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. A2, 1073, doi:10.1029/2002ja009314, 2003 Observations of the phases of the substorm I. O. Voronkov Department of Physics, University of Alberta, Edmonton,
More informationIonospheric convection signatures of tail fast flows during substorms and Poleward Boundary Intensifications (PBI)
GEOPHYSICAL RESEARCH LETTERS, VOL. 38,, doi:10.1029/2011gl046758, 2011 Ionospheric convection signatures of tail fast flows during substorms and Poleward Boundary Intensifications (PBI) Eftyhia Zesta,
More informationHighly periodic stormtime activations observed by THEMIS prior to substorm onset
GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L17S24, doi:10.1029/2008gl034235, 2008 Highly periodic stormtime activations observed by THEMIS prior to substorm onset L. Kepko, 1 J. Raeder, 1 V. Angelopoulos,
More informationRelative timing of substorm onset phenomena
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109,, doi:10.1029/2003ja010285, 2004 Relative timing of substorm onset phenomena L. Kepko Center for Space Physics, Boston University, Boston, Massachusetts, USA M.
More informationFlux transport, dipolarization, and current sheet evolution during a double onset substorm
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116,, doi:10.1029/2010ja015865, 2011 Flux transport, dipolarization, and current sheet evolution during a double onset substorm R. Nakamura, 1 W. Baumjohann, 1 E.
More informationOptical Emissions from Proton Aurora
Sodankylä Geophysical Observatory Publications (2003) 92:1 5 Optical Emissions from Proton Aurora D. Lummerzheim 1, M. Galand 2, and M. Kubota 3 1 Geophysical Institute, University of Alaska, Fairbanks,
More informationComment on "Formation of Substorm Pi2: A coherent response to auroral streamers and currents" by Nishimura et al
Comment on "Formation of Substorm Pi2: A coherent response to auroral streamers and currents" by Nishimura et al Article Published Version Rae, I. J., Murphy, K. R., Miles, D. M., Watt, C. E. J. and Mann,
More informationCurriculum Vitae. Brian J. Jackel Physics and Astronomy University of Calgary Calgary Alberta T2N 1N4 Research Interests
Brian J. Jackel Physics and Astronomy University of Calgary Calgary Alberta T2N 1N4 brian.jackel@ucalgary.ca Research Interests Curriculum Vitae Optical measurements of the aurora applied to magnetospheric
More informationPublication List for Robert L. Lysak
Publication List for Robert L. Lysak Hudson, M. K., F. S. Mozer, and R. L. Lysak, Magnetic field-aligned potential drops due to electrostatic ion cyclotron turbulence, Geophys. Res. Lett., 5, 143, 1978.
More informationSubstorm triggering by new plasma intrusion: Incoherent scatter radar observations
Click Here for Full Article JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2009ja015168, 2010 Substorm triggering by new plasma intrusion: Incoherent scatter radar observations L. R. Lyons, 1
More informationPressure changes associated with substorm depolarization in the near Earth plasma sheet
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115,, doi:10.1029/2010ja015608, 2010 Pressure changes associated with substorm depolarization in the near Earth plasma sheet Y. Miyashita, 1 S. Machida, 2 A. Ieda,
More informationResponse of morning auroras and cosmic noise absorption to the negative solar wind pressure pulse: A case study
ÓPTICA PURA Y APLICADA. www.sedoptica.es Sección Especial: 37 th AMASON / Special Section: 37 th AMASON Aurora Response of morning auroras and cosmic noise absorption to the negative solar wind pressure
More informationRadar Observations of Pulsed Ionospheric Flows at the Ionospheric Projection of the Plasmapause Produced by a Bursty Bulk Flow at Substorm Onset
GEOPHYSICAL RESEARCH LETTERS, VOL.???, XXXX, DOI:10.1029/, Radar Observations of Pulsed Ionospheric Flows at the Ionospheric Projection of the Plasmapause Produced by a Bursty Bulk Flow at Substorm Onset
More informationAuroral signature of ground. Toshi Nishimura (UCLA), Larry Lyons, Takashi Kikuchi, Eric Donovan,
Auroral signature of ground Pi 2 pulsation Toshi Nishimura (UCLA), Larry Lyons, Takashi Kikuchi, Eric Donovan, Vassilis Angelopoulos, l Peter Chi and Tsutomu Nagatsuma Long-standing discussion on Pi 2
More informationEstimation of magnetic field mapping accuracy using the pulsating aurora chorus connection
GEOPHYSICAL RESEARCH LETTERS, VOL. 38,, doi:10.1029/2011gl048281, 2011 Estimation of magnetic field mapping accuracy using the pulsating aurora chorus connection Y. Nishimura, 1,2 J. Bortnik, 1 W. Li,
More informationCharacteristics of the storm-induced big bubbles (SIBBs)
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111,, doi:10.1029/2006ja011743, 2006 Characteristics of the storm-induced big bubbles (SIBBs) Hyosub Kil, 1 Larry J. Paxton, 1 Shin-Yi Su, 2 Yongliang Zhang, 1 and
More informationDual structure of auroral acceleration regions at substorm onsets as derived from auroral kilometric radiation spectra
Click Here for Full Article JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112,, doi:10.1029/2006ja012186, 2007 Dual structure of auroral acceleration regions at substorm onsets as derived from auroral kilometric
More informationSubstorm onsets as observed by IMAGE-FUV
71 Substorm onsets as observed by IMAGE-FUV H. U. Frey and S. B. Mende 1. Introduction Abstract: The FUV instrument observed more than 4000 substorm onsets during the 5.5 years of the IMAGE mission. About
More informationEstimates of the Suprathermal O + outflow characteristic energy and relative location in the auroral oval
Estimates of the Suprathermal O + outflow characteristic energy and relative location in the auroral oval L. Andersson, W. K. Peterson and K. M. McBryde Laboratory for Atmospheric and Space Physics, University
More informationPre-Onset Azimuthal Pressure Gradient. Related to Dipolarization Fronts
Pre-Onset Azimuthal Pressure Gradient and Associated Auroral Intensifications ti Related to Dipolarization Fronts XXi X. Xing (xyxing@atmos.ucla.edu), @t d)lrl L. R. Lyons Department of Atmospheric and
More informationSolar-terrestrial coupling evidenced by periodic behavior in geomagnetic indexes and the infrared energy budget of the thermosphere
GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L05808, doi:10.1029/2007gl032620, 2008 Solar-terrestrial coupling evidenced by periodic behavior in geomagnetic indexes and the infrared energy budget of the thermosphere
More informationScaling of electric field fluctuations associated with the aurora during northward IMF
GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L20109, doi:10.1029/2006gl027798, 2006 Scaling of electric field fluctuations associated with the aurora during northward IMF B. V. Kozelov 1 and I. V. Golovchanskaya
More informationMAIN (MULTISCALE AURORA IMAGING NETWORK) AURORAL CAMERAS: OVERVIEW OF EVENTS OBSERVED DURING LAST WINTER SEASONS. Boris V. Kozelov
MAIN (MULTISCALE AURORA IMAGING NETWORK) AURORAL CAMERAS: OVERVIEW OF EVENTS OBSERVED DURING LAST WINTER SEASONS Boris V. Kozelov Polar Geophysical Institute, Apatity, Murmansk region, 184209; e-mail:
More informationWhat causes auroral arcs and why we should care? Larry Kepko NASA Goddard Space Flight Center
What causes auroral arcs and why we should care? Larry Kepko NASA Goddard Space Flight Center Aurora are the most visible manifestation of space weather. Yet despite decades of research, the magnetospheric
More informationPossible eigenmode trapping in density enhancements in Saturn s inner magnetosphere
Click Here for Full Article GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L04103, doi:10.1029/2006gl028647, 2007 Possible eigenmode trapping in density enhancements in Saturn s inner magnetosphere J. D. Menietti,
More informationSounding rocket study of two sequential auroral poleward boundary intensifications
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116,, doi:10.1029/2011ja016428, 2011 Sounding rocket study of two sequential auroral poleward boundary intensifications M. R. Mella, 1 K. A. Lynch, 1 D. L. Hampton,
More informationChapter 8 Geospace 1
Chapter 8 Geospace 1 Previously Sources of the Earth's magnetic field. 2 Content Basic concepts The Sun and solar wind Near-Earth space About other planets 3 Basic concepts 4 Plasma The molecules of an
More informationThe Substorm. Eric Donovan. Department of Physics and Astronomy University of Calgary
The Substorm Department of Physics and Astronomy University of Calgary 1. Brief statement as to why the aurora is important here 2. Modes of the Magnetosphere (driven, normal, instability) 3. The substorm
More informationSTATISTICAL STUDY OF RELATIONSHIPS BETWEEN DAYSIDE HIGH-ALTITUDE/-LATITUDE O + OUTFLOWS, SOLAR WINDS, AND GEOMAGNETIC ACTIVITY
1 STATISTICAL STUDY OF RELATIONSHIPS BETWEEN DAYSIDE HIGH-ALTITUDE/-LATITUDE O + OUTFLOWS, SOLAR WINDS, AND GEOMAGNETIC ACTIVITY Sachiko Arvelius 1, M. Yamauchi 1, H. Nilsson 1, R. Lundin 1, H. Rème 2,
More informationCharacteristics of Wave Induced Oscillations in Mesospheric O2 Emission Intensity and Temperature
Utah State University DigitalCommons@USU All Physics Faculty Publications Physics 1-2006 Characteristics of Wave Induced Oscillations in Mesospheric O2 Emission Intensity and Temperature A. Taori Michael
More informationTHE AURORA BOREALES: MORE THAN MEETS THE EYES. Jean-Pierre St-Maurice Institute of Space and Atmospheric Studies U of Saskatchewan, Canada
THE AURORA BOREALES: MORE THAN MEETS THE EYES Jean-Pierre St-Maurice Institute of Space and Atmospheric Studies U of Saskatchewan, Canada MORE THAN MEETS THE EYES! 1. What do we learn from analysis of
More informationA suggestion that two-dimensional turbulence contributes to polar cap convection for B z north
GEOPHYSICAL RESEARCH LETTERS, VOL. 39,, doi:10.1029/2012gl051347, 2012 A suggestion that two-dimensional turbulence contributes to polar cap convection for B z north M. C. Kelley 1 and H.-J. Kim 2 Received
More informationWhat determines when and where reconnection begins
What determines when and where reconnection begins Robert L. McPherron Invited presentation at Unsolved Problems in Magnetospheric Physics, Scarborough, UK, Sept. 6-12. Factors That Might Affect Tail Reconnection
More informationThe Auroral Zone: Potential Structures in Field and Density Gradients
The Auroral Zone: Potential Structures in Field and Density Gradients David Schriver May 8, 2007 Global Kinetic Modeling: week 10 Foreshock (week 3) Auroral zone (week 7) (week 8) Radiation Belt (week
More informationObservations of GPS scintillation during an isolated auroral substorm
Hosokawa et al. Progress in Earth and Planetary Science 2014, 1:16 RESEARCH Observations of GPS scintillation during an isolated auroral substorm Keisuke Hosokawa 1,2*, Yuichi Otsuka 3, Yasunobu Ogawa
More information