Ionospheric studies using a network of all-sky imagers from equatorial to sub-auroral latitudes C. Martinis, J. Baumgardner, J. Wroten, M. Mendillo, D. Hickey, B. Alford, R. Finnan Center for Space Physics - Boston University
BU Optical Network for Thermospheric Studies existing planned 1. Equatorial and low latitude Ionosphere (from magnetic equator to the crests of the Appleton Anomaly). ESF and MSTIDs, effects on trans-ionospheric radio signals using GPS and optical diagnosis. 2. Mid latitude Ionosphere (poleward from Anomaly crests to ~ 40 mag lat). Nighttime MSTIDs, E and F region coupling. 3. Sub-auroral Ionosphere (latitudes below auroral ovals). Stable auroral red (SAR) arcs (magnetic activity effects that transfer magnetospheric ring current energy into the I-T system)
Typical configuration of an imaging system Front lens (narrow, all-sky) Optical system (lenses, filters) Detector (CCD) 3
The typical airglow signatures in the thermosphere correspond to neutral O emissions at 6300 Å and 7774Å * 7774Å emission is caused by the radiative recombination of O + * O e O h 7774 * The so-called oxygen red line at 6300 Å (OI 6300 Å) represents the spontaneous de-excitation of atomic oxygen from the 1 D state to the 3 P ground state. O( 1 D) is produced mainly by two processes involving O +. The first one with O 2 and the second one, less important, with N 2 1 1 O2 e (1 ) O O( D) 1 O O O O 2 2 4
A 6300 6300 [ O ] [ N ] [ e ] 1 1 1 2 2 2 2 2 A D d D *Emission limited to 250 and 300 km. 7774 is proportional to [O + ] [e - ]. I ( Rayleighs) 10 dh 6 6300 6300 * Combining intensities of these two emissions: max Tinsley, 1973; Makela et al, 2001 h I I 7774 6300 5
630.0 nm Airglow: ESF, MSTIDs and SAR arcs NASA, ISS From Baumgardner et al., 2013 ESF MSTIDs From Kelley et al., 2003
ESF structures www.buimaging.com El Leoncito (31 o S, -18 o mag) ~900 km Apex height ~ 1700 km Apex height Arecibo (16 o N, 23 o mag) ~1800km Apex height 7
a. ESF depletions observed at both hemispheres 9
Proper comparison: map Arecibo structures to the Southern hemisphere MER unwarped ARE unwarped + mapped * Excellent correlation Longitudinal extent now similar at both sites * Depletions at MER not reaching the ARE conjugate point: not enough contrast? northward winds? 0028UT 0023UT 0135UT 0129UT 10
b. Speed * *
c. Intensity 3/10/15 11/29/14 * different background * Weaker B field * Thinner structures * Northward wind
1 June 2013 storm ESF effects at midlatitudes 40 deg magnetic latitude, L~ 1.7 (Martinis et al, 2015; Kil et al. 2016; Martinis et al., 2016)
From Martinis et al., 2015
Courtesy A. Coster
From Martinis et al., 2016
MSTIDs: Bands moving north(south)-westward in the southern(northern) hemisphere. Radially outward E fields Enhancements in airglow brightness related to TEC enhancements What about ΔTEC/min?: 0.3 TECU/min (for ESF ~ 1-2 TECU/min) 21
MSTIDs : Airglow changes; TEC changes; E-F region coupling -25 GPS data showing TEC variations All-sky images from El Leoncito, showing moving northwestward bright bands moving northwestward TEC maps courtesy of M. Nishioka
Climatology is relatively well understood: American and European sectors show peak activity in both solstices. Coupling between E and F regions and inter-hemispheric coupling play crucial roles. (from Martinis et al., 2011) (from Martinis et al., 2015) 23
E- F region coupling Initial distribution of Fe+ at 102km altitude. Two rods aligned NW-SE. Westward wind in the E region. F-region suitable for Perkins instability Haldoupis et al.,2003 Courtesy Tatsu Yokoyama
For non-typical MSTIDs observations: holes in Fe+ density, Bright-only bands are produced. Thus, depending on the structure of Es layers and F-region winds condition in terms of the Perkins instability, bright-bands are explained
MSTIDs: C/NOFS and ASIs
Feb17 2010 280 290 300 3:20 UT (5:05 UT) 6:50UT
(1)E* mer and E* zon fluctuations consistently in phase (2)V* mer and V* zon as well as B* mer and B* zon about 180 out of phase; (3)components of V* and B* varied out of phase with each other. Burke et al, 2016 explained phase offsets based on Alfven waves properties: 1- the B* and E* vectors lie in orthogonal planes. 2- If both components of E* have the same signs, B* components must have opposite polarities. B * E * Bˆ V B Am N V * */ 0 i p i A B0 B0 Thus the phase relationships between the measured components of E*, B* and V* are consistent with an Alfvén wave explanation. 0 S E* * ( * ˆ * ˆ) ( * ˆ * ˆ B E mer E zon B mer B zon ) o E * mer B * zon E * zon B * mer Bˆ (2) o o
W S ˆ 0.8 [ E * ( / ) * ( ) * ( / ) * ( )] 2 mer mv m B zon nt E zon mv m B mer nt B m Burke et al., 2016 S positive Energy flowing from the southern hemisphere
280 290 300 Feb09 2010
Stable auroral red (SAR) arcs BU Millstone Hill Aurora SAR arc USU/BAS Rothera(M. Taylor-T.Moffat) From Kozyra et al, 1997
1 June 2013 * Observation of SAR arcs in both hemispheres: *First conjugate ground-based detection of SAR arcs * Morphology not exactly the same; e.g., Rothera s SAR arc shows sharper poleward edges
SAR Arc positions on 1 June 2013 at: Millstone Hill Rothera
31 May-01 June 01 June 00 UT- 09 UT
North
Comparison with models BU airglow code to obtain Background brightness MSIS + IRI; TIEGCM;GITM To model SAR arc, need to incorporate a ring-current-ionosphere coupled model
Van Allen Probes to measure ring current ion populations All-sky images mapped into the equatorial plane
(a) (b) (b) HOPE and EMFSIS data for VAP B and A, The location of the plasmapause coincides with the increase in fluxes in the three ions between ~ 8:00UT and 08:20UT. VAP B is ahead and it samples field lines that connect the sub-auroral ionosphere where a SAR arc is being measured by the MH ASI located to the west
X ASIs images mapped into the geomagnetic equatorial plane at 13:00, 13:24 and 13:31 UT. The Sun is at the bottom and dusk to the left (viewed from the south pole). A SAR arc is observed close to L=3. The red X indicates the satellite location at the image time
We want to investigate how ring current properties could be related to SAR arc characteristics Time variations of H+ fluxes with initial energy peaking at 10 kev (top) and 40 kev (middle) in a background of thermal plasma (1 ev, density = 2000 cm -3 ). Rate of energy loss as a function of ion energy (bottom) (from Fok et al., 1993) Energy loss experienced by ring current ions traveling through: (a) thermal electron gas with temperature 5800K and density 1000 cm -3 (Kozyra et al., 1997); (Kozyra et al., 1993)
03/07/2013 777.4 nm 630.0 nm 70 W
Survey Operations Ion Velocity Meter pointed to ram, imaging instrument views to port. Operates in this configuration >90% of mission. Conjugate Operations Set of yaw maneuvers to provide winds at both magnetic footpoints Courtesy T. Immel)
Summary Network of all-sky imagers allows the study of ionospheric processes from low to sub-auroral latitudes Large Ni perturbations are not always present when airglow bands are observed (Plasma blobs and MSTIDs). Satellite measurements provide S values that can help to determine source region of MSTIDs First ground-based conjugate observations of SAR arcs indicates similar morphologies. Simultaneous VAP data can be used to quantify M-I coupling at subauroral latitudes. Presence of low energy ions might validate Coulomb collisions as the mechanism providing energy source of SAR arcs Ground-based support for ICON and GOLD
TEC waves- Otsuka et al, 2013 Kuhlunsburg 54 o geo lat Inclination = 69 o
300 km 75 ZA dashed circle 400 km 75 ZA solid circle