CISM Radiation Belt Models CMIT Mary Hudson CISM Seminar Nov 06

Van Allen Radiation Belts inner belt outer belt Slot region

Van Allen Belts-Plasmasphere Overlap Ring current

Solar Cycle Dependence of 2-6 MeV Electrons Li et al., GRL, 2006

Van Allen Radiation Belts: Slot region variability inner belt outer belt Slot region SAMPEX electrons: MeV slot region L = Outer belt inner belt

slot region new belt Effect on the Radiation Belts [Baker et al., 2004, Nature]

March 91 Shock Acceleration 3.5 MeV at L=6.6, t=0 (M =11,150 MeV/G) Elkington et al., JASTP, 02; 04

MHD-Guiding Center Simulation Elkington et al., JASTP, 2002; 2004

SAMPEX >10 MeV Electron Injections

SAMPEX: Mar 91 decay+Feb 94 injection

Halloween 03 >10 MeV Electron Injections

Global LFM-MHD Simulations of Magnetosphere Solar wind measurements made WIND, ACE or IMP8 (Feb 94, not Mar 91) Solar wind measurements made WIND, ACE or IMP8 (Feb 94, not Mar 91) Ideal MHD equations are solved on a computational grid to simulate the response of the magnetosphere Ideal MHD equations are solved on a computational grid to simulate the response of the magnetosphere

1994 Feb 21 Event: density

1994 Feb 21 Event: E phi

Halloween ’03 Shock Injection initial E ~ 5 MeV, R ~ 6 RE, final E ~15 MeV, R ~ 2.5 RE Kress et al., 06

Halloween ’03 Shock Injection of >10 MeV (W0=1-7 MeV) Electrons

E_phi (left) and Solar Energetic Electron Trajectory (right) Halloween ‘03 solar energetic electron injection event Kress et al., 2006

Low altitude SAMPEX observations of > 10 MeV electrons, injected 10/29/03 Low altitude SAMPEX observations of > 10 MeV electrons, injected 10/29/03 E -1.5 electron energy spectrum from several MeV to > 15 MeV Initially not observed at SAMPEX due to eq injection Simulated pitch angle distribution->

Outer Belt Losses Due to Whistler Pitch Angle Scattering Hiss Whistler Mode outer belt 2-6 MeV Slot Variability: [Lyons et al., 1972]

Losses due to Pitch Angle Scattering VLF waves from p’sheet electrons EMIC waves from ring current ions

MHD Fields Injection of RadBelt Electrons Elkington et al., JASTP, 2004

MHD Fields Injection of RadBelt Electrons Elkington et al., JASTP, 2004

Diffusion Rates vs. L Radial diffusion rates in model ULF wave fields D_LL ~ L N Perry et al., JGR, 05, includes δEφ, δBr, δB//, freq and L-dependent power Braughtigam & Albert, 2000, N=6, 10; Perry et al., 2006, N=6, 12 Radial diffusion rates in model ULF wave fields D_LL ~ L^N Perry et al., JGR, 2005, Include δEφ, δBr, δB//, freq and L-dependence 3D trajectories N ~ 6 for no L-dep power, N ~ 12 with L dependence M=273 MeV/G M=273 MeV/G Tau(L,E) Summers 04 # # Selesnick & Blake 2000 # # # Elkington et al., 2003

Solutions to diffusion equation using DLL from model ULF wave fields & and PSD from CRRES measurements in subsequent 10-hr orbits to update inner and outer boundaries Dashed lines show CRRES measurements of PSD 61 days apart. Loss model based on Summers et al Perry et al DLL=10-2(L/4)^12 day-1

MHD-Driven Phase Space Density AE8 Max-Initialized, Sept 98 StormFei et al., 2006 MHD-Test Particle Radial Diffusion

New belt example: 24 Nov 2001 Clear trapping of solar particles: 13 of 26 SEP penetration events inside L=4, Mazur et al., AGU Monograph 165, 2006

Conclusions Drift time scale injection of multi- MeV electrons: Strong compression of dayside magnetopause due to high speed CME Drift time scale injection of multi- MeV electrons: Strong compression of dayside magnetopause due to high speed CME Relativistic electron seed population at and beyond geosynchronous required Relativistic electron seed population at and beyond geosynchronous required Plasmasphere plays role intensifying E_phi Plasmasphere plays role intensifying E_phi Long-lived, energetic trapped population injected into slot region Long-lived, energetic trapped population injected into slot region Well-described by CMIT without coupled RCM Well-described by CMIT without coupled RCM Intermediate storm timescale (hrs,days): changes in PSD described by radial diffusion & loss due to whistler (and EMIC) scattering Intermediate storm timescale (hrs,days): changes in PSD described by radial diffusion & loss due to whistler (and EMIC) scattering Enhanced D_LL due to ULF waves needs further study with RCM coupled to CMIT, plasmasphere, ion outflow to populate m’sphere during IMF Bz<0 Enhanced D_LL due to ULF waves needs further study with RCM coupled to CMIT, plasmasphere, ion outflow to populate m’sphere during IMF Bz<0

Drift Time Scale Injection from SSC’s Drift Time Scale Injection from SSC’s Blake et al., 2005

Mar 91-Feb 91Comparison