Kinetic Alfvén Waves in the Inner Magnetosphere Triggered by an Interplanetary Shock David Malaspina 1, Seth Claudepierre 2, Kazue Takahashi 3, Allison Jaynes 1, Scot Elkington 1, Robert Ergun 1, John Wygant 4, Geoff Reeves 5, Craig Kletzing 6 1 University of Colorado / LASP 2 The Aerospace Corporation 3 Applied Physics Laboratory 4 University of Minnesota 5 Los Alamos National Laboratory 6 University of Iowa RBSP SWG July, /29/15

E  FAC log 10 ( keV / (keV cm 2 s str)) log 10 (mV/m) 2 / Hz log 10 nT 2 / Hz Shock-Impact Context Shock Response wave E-field wave B-field |B| ~One orbit (~9 hrs) MagEIS e- HOPE e- HOPE H+ MagEIS H+ Broadband waves begin 7/29/15 Probe B 02 Oct. 2013

log 10 ( keV / (keV cm 2 s str)) log 10 nT 2 / Hz E  FAC wave E-field wave B-field HFR MagEIS e- HOPE e- HOPE H+ MagEIS H+ B || FAC Slowly damping ULF Wave (3.6 mHz, fundamental toroidal mode) < 100 eV H+ response > 10 keV e- response > 10 keV H+ response < 30 eV e- response Inside plasmasphere ~ 300 cc Broadband EM waves Up to ~ 300 Hz 7/29/15 log 10 (mV/m) 2 / Hz [Malaspina (in progress)] Interval of burst data (continuous 1,024)

When Alfven wave λ  approaches ion gyro scale (ρ i or ρ S ): Group velocity component  to B develops E || develops, supported by electron pressure Waves become more electrostatic at higher frequencies From KAW dispersion relation [Stasiewicz+ 2000] Assume (k  > k || ) and (v Alfven > v Flow ) --> Then: ω sc ≈ k / |v Flow | When (Ti > Te), as observed in this interval: [Chaston+ 2014] Measured by FGM From upper hybrid line From wave data One free parameter: Ion thermal velocity Ion flow speed (s/c frame) KAW theory 7/29/15

Fits to KAW Theory KAW E/B fit Blue lines (< 2 Hz): DC-coupled 64 S/s FGM 64 S/s Black lines (> 2 Hz): DC-coupled 1024 S/s SCM 1024 S/s this 16 s interval Reduces to V Alfven at low freq. One free parameter Phase of +/-90° --> Standing wave Phase of 0, +/-180° --> Traveling wave Standing wave at LF (consistent w/ field-line resonance) Global in scope ! Observed at multiple ground magnetometers with wide MLT spacing 7/29/15 [Malaspina (in progress)]

Black curve is v plasma from (E = - v x B) Plasma is sloshing past the spacecraft (!) 7/29/15 Fits to KAW Theory [Malaspina (in progress)]

KAW Free parameter: Vi ion thermal velocity ---- = Vf ion flow velocity (s/c frame) As v plasma -> 0 Vi / Vf increases (!) The single fit parameter follows expected ion flow behavior 7/29/15 Fits to KAW Theory [Malaspina (in progress)]

7/29/15 Global Nature RBSP-B SJG HON GUA RBSP-B

7/29/15 KAW Acceleration / Heating Kinetic-scale field line resonances Extension of macro-scale FLR to small-scales 10’s of mHz in plasma frame Doppler-shifted to 10 – 1000 Hz range (s/c frame) Possible acceleration mechanisms: E || Landau resonance Gyro-scale E-fields can demagnetize ion motion, enabling stochastic acceleration and/or heating [Chaston+ 2014] [Chaston+ 2010, 2012]

7/29/15 Conclusions (1)Broadband waves observed inside the plasmasphere on 02 Oct Wave properties consistent with kinetic Alfvén waves (2) Kinetic Alfvén Wave power is modulated by ULF activity (3) ULF response is global in nature, implying prompt, global generation of kinetic-Alfvén waves in response to an interplanetary shock impact (4) 02 October 2013 Sequence of events (red = inferred): Interplanetary Shock --> Compressed Magnetosphere --> Global ULF wave response --> Coupling to small scales --> Kinetic Alfvén Waves --> Wave-particle interaction (?)

7/29/15 Questions?

What are these HF waves? No coherent structures e.g. double layers, phase space holes No narrowband waves No resonant wave growth Similar modulation in E and B Alfvénic? E-fields have more power at HF Broadband, Alfvénic, electrostatic at HF, parallel E-field = Kinetic Alfvén Waves(?) Wave power < 8 Hz removed 7/29/15