cismsem1

CISM Radiation Belt Models: 

CISM Radiation Belt Models CMIT Mary Hudson CISM Seminar Nov 06

Slide2: 

Van Allen Radiation Belts inner belt outer belt Slot region

Van Allen Belts-Plasmasphere Overlap: 

Van Allen Belts-Plasmasphere Overlap Ring current

Solar Cycle Dependence of 2-6 MeV Electrons : 

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

Slide5: 

Van Allen Radiation Belts: Slot region variability inner belt outer belt Slot region SAMPEX electrons: 2 - 6 MeV slot region L = 2 - 3 Outer belt inner belt

Slide6: 

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

March 91 Shock Acceleration: 

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: 

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

SAMPEX >10 MeV Electron Injections: 

SAMPEX >10 MeV Electron Injections

SAMPEX: Mar 91 decay+Feb 94 injection: 

SAMPEX: Mar 91 decay+Feb 94 injection

Halloween 03 >10 MeV Electron Injections: 

Halloween 03 >10 MeV Electron Injections

Global LFM-MHD Simulations of Magnetosphere: 

Global LFM-MHD Simulations of Magnetosphere 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

1994 Feb 21 Event: density: 

1994 Feb 21 Event: density

1994 Feb 21 Event: Ephi: 

1994 Feb 21 Event: Ephi

Halloween ’03 Shock Injection initial E ~ 5 MeV, R ~ 6 RE, final E ~15 MeV, R ~ 2.5 RE: 

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: 

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

E_phi (left) and Solar Energetic Electron Trajectory (right): 

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

Slide19: 

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->

Slide20: 

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: 

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

MHD Fields Injection of RadBelt Electrons: 

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

MHD Fields Injection of RadBelt Electrons: 

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

Diffusion Rates vs. L : 

Diffusion Rates vs. L Radial diffusion rates in model ULF wave fields D_LL ~ LN 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 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 : 

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. 2004. Perry et al. 2005 DLL=10-2(L/4)^12 day-1

MHD-Driven Phase Space Density: 

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

New belt example: 24 Nov 2001: 

New belt example: 24 Nov 2001 Clear trapping of solar particles: 13 of 26 SEP penetration events inside L=4, 98-03 Mazur et al., AGU Monograph 165, 2006

Conclusions: 

Conclusions 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 Plasmasphere plays role intensifying E_phi Long-lived, energetic trapped population injected into slot region 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 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: 

Mar 91-Feb 91Comparison