Drift-bounce resonance between Pc5 wave and ions: Arase and MMS study

Transcription

1 Drift-bounce resonance between Pc5 wave and ions: Arase and MMS study S. Oimatsu1, M. Nosé2, M. Teramoto2, K. Yamamoto1, A. Matsuoka3, S. Kasahara4, S. Yokota5, K. Keika4, G. Le6, R. Nomura7, A. Fujimoto8, D. Sormakov9, O. Troshichev9, Y. M. Tanaka10, M. Shinohara11, I. Shinohara3, Y. Miyoshi2, J. A. Slavin12, R. E. Ergun13, and P. A. Lindqvist14 1 Graduate School of Science, Kyoto University, 2 Institute for Space-Earth Environmental Research, Nagoya University, 3 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 4 Graduate School of Science, The University of Tokyo, 5 Graduate School of Science, Osaka University, 6 Heliophysics Science Division, NASA Goddard Space Flight Center 7 Environmental Test Technology Unit, Japan Aerospace Exploration Agency, 8 International Center for Space Weather Science and Education, Kyusyu University, 9 Arctic and Antarctic Research Institute, 10 National Institute of Polar Research, 11 National Institute of technology, Kagoshima College, 12 Department of Climate and Space Sciences and Engineering, University of Michigan, 13 Department of Astrophysical and Planetary Sciences, University of Colorado, 14 Royal Institute of Technology Oimatsu, S., Nosé, M., Teramoto, M., Yamamoto, K., Matsuoka, A., Kasahara, S., et al. (2018). Drift bounce resonance between Pc5 pulsations and ions at multiple energies in the nightside magnetosphere: Arase and MMS observations. Geophysical Research Letters, 45,

2 Wave period: Pc4 : s Pc5 : s Sources Features External Kelvin-Helmholtz (K-H) instability Solar wind dynamic pressure Small m-number Toroidal mode Internal Plasma instability due to the ring current or substorm injection Large m-number Poloidal Mode E+ E- E+ E- E+ ω mω d = Nω b Particles Equator Particles ω : Wave angular frequency m : Azimuthal wave number (m-number) ωb : Bounce angular frequency ωd : Drift angular frequency N : Integer [Ren et al., 2017] Odd harmonic N=2k Even harmonic N=2k+1 (k : Integer, -2 < N < 2)

3 Li et al., 1993 Oxygen ions are diffused by the drift-bounce resonance with convection electric field (simulation). Drift-bounce resonance of O + ion contributes to the acceleration or deceleration of O + ions [e.g., Li et al., 1993; Yang et al., 2011]. Mitani et al., 2018 Mitani et al. (2018) proposed that the drift-bounce resonance contribute to the deeper penetration of > 200 kev O + ions into the inner magnetosphere.

4 Arase satellite MGF - 8-s magnetic field MEP-i - 16-s data (NML mode) - H +, He ++, He +, O +, O +2, O2 + - Energy range: 5.1 ~109.6 kev MEP-e - 8-s data - Electron (e - ) - Energy range: 7.0~87.5 kev Launch Date December 20, 2016 Orbit Altitude Inclination < ~31 Type of Orbit Period Spin period Perigee: ~460 km Apogee: ~6 Re Elliptical orbit ~8 hours ~8 sec MMS1 satellite FGM - Magnetic field EDP - Electric field Ground stations (TIK, PBK ) Magnetic field [Miyoshi et al., 2017]

5 Case study : 27 March 2017 E L=3 L=5 L= ZSM [RE] L=7 MMS1 MMS1 0 ZSM [RE] S Arase SArase L=3 E E S S L=5 1 2 (S)1820UT(S)1820UT 1 (E)1910UT (E)1910UT -1 Arase S Arase S E -2 SE S E -3MMS1 E MMS1 (c) (S)1820UT 78 (E)1910UT Geographic Latitude [ ] (S)1820UT(S)1820UT (E)1910UT(E)1910UT MLT00 MLT /03/ UT 2017/03/ UT (c) (b) Geographic Latitude [ ] 2017/03/ UT 2017/03/ UT (a) (b) (a) L-MLT plane /03/ E 74 S TIK 72 Arase 70 E A Meridional 68plane -4 S68-4 L=11 66 L= MLT06 MLT /2 Geographic Lon [R2ESM ] )1/2 [RE] (X SM+Y (X Geogr SM)SM+Y 2017/03/ UT E L=9 L= UT Footprints (c) 80 (g) /03/27/ UT 2017/03/27/ UT MGF Br MGF Ba MGF Bp (f) FGM Br (e) MGF MGF MGF Ba Br Bp Latitude [ ] Geographic (d) (S)1820UT 78 (E)1910UT (d)10 10 Br Arase Arase Br MMS1 E Ba Arase (e)20 Arase Ba 0 TIK 0S 72 PBK Arase E Bp (f) Arase Arase Bp S (g)664 6 MMS1 Br MMS Geographic 0 Longitude [ ] -2 FGM Br /2 ) [RE] M MM L MLT(hr) MLAT Arase MMS EaBr Ea

6 OMNI HRO 1min BZ GSM OMNI HRO 1min flow speed [km/s] OMNI HRO 1min Pressure [npa] Kyoto Prov. AE OMNI HRO 1min SYM H IMF Bz Solar wind speed Dynamic pressure AE index SYM-H hhmm Mar 27 Event Tue May 15 16:08:

7 Arase B radial Pc4 Pc5 Arase B azimuthal Arase B parallel MMS1 B radial E azimuthal Pc4 Pc5 Ground (North-South) TIK PBK Arase, MMS1, and ground magnetometers observed Pc4 and Pc5 waves. The wave amplitude of the Pc5 is largest in the azimuthal direction. The Pc5 wave is observed on the ground. Wave period of the Pc5 wave is ~450 s. Ea leads Br in the southern hemisphere. Fundamental mode.

8 Frequency [mhz] Frequency [mhz] ERG Br ERG Ba a) Power [nt 2 /Hz] MGF,MMS1,TIK,PBK/ UT MGF Br MMS1 Br TIK PBK MMS1 Ea Frequency [mhz] Power (Green) [(mv/v) 2 /Hz] Pc4 Pc5

9 Nightside Dayside KIAN PBK ~Dawn ~Noon KAKO FSIM TIK GILL BRN ~Dusk NAIN DIK NAQ ABK AMD

10 m = Δθ Δϕ Phase difference : Longitudinal separation Δθ We determine which provides the maximum crosscorrelation coefficient at UT. Δθ = 192! Δϕ = 13! Δθ = 316! Δϕ = 30.4! Estimated values are consistent with the ground observation.

11 H + O + e -

12 MEP-i H + [kev] MEP-i O + [kev] MEP-e e - [kev] MEP-i O + /H + [kev] A L 5.39 A MLT(hr) 1.54 M L 6.54 M MLT(hr) 2.37 hhmm Mar 27 H + Dispersion O + Dispersion e - No dispersion O + /H /03/27/ UT Residual flux : ΔJ=(J-J1)/J1 (J1: 10-min moving average) Residual flux [arbitrary unit] Power [1/Hz] Ratio Power [1/Hz] (b) Power spectra MEP-i/H + / UT H + O kev 87.8 kev 70.3 kev 56.3 kev 45.1 kev 36.2 kev 29.0 kev 23.3 kev 18.6 kev 15.0 kev 12.0 kev 9.7 kev 7.8 kev 6.3 kev 5.1 kev Frequency (mhz) (c) MEP-i/O + / UT kev 87.8 kev 70.3 kev 56.3 kev 45.1 kev 36.2 kev 29.0 kev 23.3 kev 18.6 kev 15.0 kev 12.0 kev 9.7 kev 7.8 kev 6.3 kev 5.1 kev Frequency [mhz] Large flux oscillations of H + fluxes at > 50 kev, and that of O + fluxes at > 50 kev and < 20 kev. O + /H + flux ratio show the enhancements corresponding to the O + flux oscillations.

13 ? Energy [kev] f=3mhz f=1.75mhz f=3mhz f=1.75mhz H + O m Energy [kev] f=3mhz N=0 N=0 N=2 f=1.75mhz f=3mhz f=1.75mhz N= m Resonance mode Theoryetical resonance energy Observational energy of large flux oscillations (observation) Consistency (Theory vs observation) H + N=0 Drift resonance (ω ~ mωd) ~ kev > 56 kev N=2 Bounce resonance (ω ~ 2ωb) kev Out of energy range of MEP-i O + N=0 Drift resonance (ω ~ mωd) ~ kev > 56 kev N=2 Bounce resonance (ω ~ 2ωb) ~3-9 kev ~5 18 kev

14 Flux oscillations of H + and O + ions at > 50 kev are caused by drift resonance and those of O + ions at < 20 kev are caused by bounce resonance. We simultaneously found the drift resonance and bounce resonance of O + ions at multiple energies in the nightside inner magnetosphere. The enhancement of O + /H + flux ratio at low-energy band ( 23.3 kev) is mainly caused by selective acceleration of O + ions due to the bounce resonance for O + ions ( 18.6 kev) Mitani et al. (2018) proposed that the drift-bounce resonance contribute to the deeper penetration of > 200 kev O + ions into the inner magnetosphere. The solar wind may generate the Pc5 wave through K-H instability and it feeds energy to the O + ions through the bounce resonance. Energy transfer Solar wind ULF waves Resonance O + ions?

15 Footprint is in Russia Northern hemisphere Southern hemisphere Can I use any SuperDARN data?

16 Fundamental Pc5 wave and a Pc4 wave were observed by Arase, MMS1, and ground stations (TIK and PBK) in the postmidnight region in the storm recovery phase on 27 March The Pc5 waves is considered to be excited by solar wind. m-number of the Pc5 wave is estimated by satellite observation and ground observation to be m=-10 to -15. The e - flux oscillation is not caused by the drift-bounce resonance, while, large ion flux oscillations are attributed to the drift resonance for H + and O + ion (> 50 kev), and to the bounce resonance for O + ion (< 20 kev). O + /H + flux ratio shows enhancements corresponding to the O + ion flux oscillations, which suggest the selective acceleration of O + ions.