Simulated prompt acceleration of multi- MeV electrons by the 6-7 - PowerPoint PPT Presentation

Simulated prompt acceleration of multi- MeV electrons by the 6-7 September 2017 interplanetary shock Mary K. Hudson, Shri Kanekal, Zhao Li, Maulik Patel, John Wygant Dartmouth, NCAR/HAO, NASA GSFC, UMN

Outline • IP-shock compressions of dayside m’sphere launch fast mode impulse • Accelerates electrons azimuthally & transports radially inward conserving μ • Strong events rare, RBSP measurements see weaker events, pitch angle dispersed drift echoes • 17 March 2015; 8 Oct 2013;16 July 2017; 6 Sept 2017;

CRRES March 91 Electron Injection Event: Not diffusive! Transport >1 Re over drift period Oct. 1991 July 1990 (Courtesy of J. B. Blake ) March 24, 1991

Solar Wind Shock Pair 9/6-9/8

Van Allen Probes 6 September 2017 23:30 – 00:30 UT Shock arrives 23:45 UT 5

REPT A REPT B 140. Alpha (degrees) 1.8 MeV cm 120. 1 06 - 2 s - 1 sr 100. - 1 MeV 80. 1 05 - 1 60. 140. Alpha (degrees) 2.1 MeV 1 06 cm 120. - 2 s - 1 sr 100. - 1 MeV 1 05 80. - 1 60. 10×10 5 8×10 5 140. 6×10 5 Alpha (degrees) 2.6 MeV cm 4×10 5 120. - 2 s ULF osc 2×10 5 - 1 sr 100. - 1 MeV 80. - 1 60. 140. 1 05 3.4 MeV Alpha (degrees) cm 120. - 2 s - 1 sr 100. 1 04 - 1 MeV 80. - 1 60. 1 03 140. Alpha (degrees) 4.2 MeV cm 1 04 120. - 2 s - 1 sr 100. - 1 MeV 1 03 80. - 1 60. 1 02 4000. 140. 5.2 MeV Alpha (degrees) cm 2000. 120. - 2 s - 1 sr 100. - 1 MeV 80. - 1 60. 400. 140. 6.3 MeV Alpha (degrees) cm 200. 120. - 2 s - 1 sr 100. - 1 MeV 80. - 1 60. 23:42 23:45 23:48 23:51 23:54 23:57 L 4.047 4.112 4.174 4.239 4.298 4.356 6 2017-09-06 (249) 23:42 to 23:59

EFW E-field Measurements

CRRES Data from ~2200 MLT Drift echoes Li et al., GRL, 1993

Prompt acceleration of magnetospheric electrons to ultrarelativistic energies by the 17 March 2015 interplanetary shock VAP-A at L ~ 3 Kanekal et al., JGR, 2016 Journal of Geophysical Research: Space Physics Volume 121, Issue 8, pages 7622-7635, 15 AUG 2016 DOI: 10.1002/2016JA022596 http://onlinelibrary.wiley.com/doi/10.1002/2016JA022596/full#jgra52812-fig-0002

S/C Location at IP Shock Arrival 17 March 2015

Global MHD Simulations of Magnetosphere +Test Particles • Observations of the solar wind parameters made by satellites, operating at the L1 point (OMNI data) • The ideal MHD equations are solved on a grid to simulate the response of the magnetosphere to the dynamic solar wind – • Lyon-Fedder-Mobarry model coupled to ionospheric BC & RC

Simulated Pitch Angles at RBSP-A 17 March 2015 Shock Hudson et al., JGR, 2017

Simulated RB-A Weighted Flux L ~ 3

Simulated RB-B Weighted Flux L ~ 5

Simulated Pitch Angles at RBSP-B

Drift Shell Splitting Effect on PAD Depends on Radial Gradient Sibeck et al., JGR, 1987

Normalized REPT Flux at RB-B Van Allen Probe – B at L~5 Baker et al, 2016 17 March 2015 IP Shock Injection Event extended

LFM Ephi Snapshots 17 March 2015 IP Shock Faraday’s Law: ∂Bz/∂t = -  x Ephi

2 MeV electrons – 3D Pitch Angles – Eq Plane Crossing in LFM-RCM Fields 17 March 2015 IP Shock Event

Van Allen Probes 6 September 2017 23:30 – 00:30 UT Shock arrives 23:45 UT 21

ECT Flux Distribution Prior to Shock for 6 Sept 2017 Storm

6 Sept 2017 L* = 3.9 – 4.6

Pitch Angle Distributions at Probe A 6 Sept 2017 ULF osc

REPT A REPT B 140. Alpha (degrees) 1.8 MeV cm 120. 1 06 - 2 s - 1 sr 100. - 1 MeV 80. 1 05 - 1 60. 140. Alpha (degrees) 2.1 MeV 1 06 cm 120. - 2 s - 1 sr 100. - 1 MeV 1 05 80. - 1 60. 10×10 5 8×10 5 140. 6×10 5 Alpha (degrees) 2.6 MeV cm 4×10 5 120. - 2 s 2×10 5 - 1 sr 100. - 1 MeV 80. - 1 60. 140. 1 05 3.4 MeV Alpha (degrees) cm 120. - 2 s - 1 sr 100. 1 04 - 1 MeV 80. - 1 60. 1 03 140. Alpha (degrees) 4.2 MeV cm 1 04 120. - 2 s - 1 sr 100. - 1 MeV 1 03 80. - 1 60. 1 02 4000. 140. 5.2 MeV Alpha (degrees) cm 2000. 120. - 2 s - 1 sr 100. - 1 MeV 80. - 1 60. 400. 140. 6.3 MeV Alpha (degrees) cm 200. 120. - 2 s - 1 sr 100. - 1 MeV 80. - 1 60. 23:42 23:45 23:48 23:51 23:54 23:57 L 4.047 4.112 4.174 4.239 4.298 4.356 25 2017-09-06 (249) 23:42 to 23:59

6 Sept 2017 L* = 5.22 – 5.11

Pitch Angle Distributions at Probe B 6 Sept 2017

Pitch Angle Distributions at Probe A 6 Sept 2017 ULF osc

Conclusions • Prompt increase of MeV el flux L = 3-5 on electron drift time scale due to IP shock launched MHD fast mode • Observed for weaker events by VAP than 24 March 1991: 8 Oct 2013; 17 March 2015; 6 Sept 2017; 16 July 2017 • MHD-test particle simulations reproduce energy, drift echo & pitch angle distributions & ULF- local flux oscillations • Observed commonly for weaker IP shocks • Strong events with Ephi ~ 100 mV/m inject el to low L~2.5 and high energy • Weaker events with Ephi ~ 10 mV/m transport into L = 3-5, lost promptly with inward magnetopause motion, drift shell splitting, m’pause shadowing

September 2017 events - REPT 2.6 MeV 3.4 MeV 4.2 MeV 5.2 MeV 30

Backup Slides

Adiabatic trajectories launched from midnight and noon in TS89 Butterfly Pancake Contours of constant L* Roederer and Lejosne,JGR, 2018

Backup Add’l REPT Channels 6 Sept 2017 VAP -A

Backup Add’l REPT Channels 6 Sept 2017 VAP -B

Van Allen Probes 6 September 2017- Including Pre-Shock GSE X (RE) GSE Y (RE) -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 6 6 3 3 2017/09/06 22:30:00 - 2017/09/06 23:30:00 UTC 2017/09/06 22:30:00 - 2017/09/06 23:30:00 UTC 2 2 5 5 1 1 4 4 GSE Z (RE) GSE Z (RE) 0 0 3 3 -1 -1 2 2 -2 -2 RBSP-A RBSP-B 1 1 -3 -3 GSE Y (RE) GSE Y (RE) -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 GSE Y (RE) 0 0 GSE X (RE) -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 3 3 2017/09/06 22:30:00 - 2017/09/06 23:30:00 UTC -1 -1 2 2 -2 -2 1 1 GSE Z (RE) GSE Z (RE) -3 -3 0 0 -4 -4 -1 -1 -5 -5 -2 -2 RBSP-A RBSP-A RBSP-B RBSP-B -6 -6 -3 -3 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 GSE X (RE) GSE X (RE) 35

REPT-A Lower Energies 6 Sept 2017

REPT-B Lower Energies 6 Sept 2017

September 2017 events - REPT 2.6 MeV 3.4 MeV 4.2 MeV 5.2 MeV 38

7 Oct 2013 IP shock Figure 4 Foster et al., JGR, 2015

ECT Flux Preceding 17 March 2015 IP Shock Arrival RB-B Location at IP Shock Arrival RB-A Location at IP Shock Arrival

VAP Locations for Second Shock