# Presentation: 632795

##  Effects of Coronal Mass Ejections and Solar Wind Streams on the Earth’s Radiation Belts

- _D.N. Baker_, S. Kanekal, X. Li, S. Elkington
- Laboratory for Atmospheric and Space Physics
- Department of Astrophysical and Planetary Sciences
- University of Colorado - Boulder

## Adiabatic Invariants

*M*:  perpendicular motion
*K*:  parallel motion
*L*:  radial distance of eq-crossing in a dipole field

- Associated with each motion is a corresponding *adiabatic invariant:*

*If the fields guiding the particle change slowly compared to the characteristic motion, the corresponding invariant is conserved.*

- Gyro:  *M=p**2**/2m**0**B*
- Bounce:  *K*
- Drift:  *L*

## The Earth’s Radiation Belts

- Contours of the omnidirectional flux (particles per square centimeter per second) of protons with energies greater than 10 MeV

- Contours of the omnidirectional flux of electrons with energies greater than 0.5 MeV

## The South Atlantic Anomaly Region

**TOPEX (1992-1998)** and **TERRA-MODIS (2001)**

## Solar Activity Cycle

## The Disturbed Solar Wind: Coronal Mass Ejections (CMEs)

- Occur most often near the peak of the Sun’s 11-year activity cycle
- Propel >109 tons of matter into interplanetary space
- Can travel at speeds exceeding 2000 km/s
- Drive interplanetary shocks
- Can trigger geomagnetic storms when they impact Earth’s magnetosphere

## Coronal Mass Ejection - Earth Impact

- Courtesy of NASA

## Impulsive Injection Due to Shock Wave

*[Li et al., 1993]*

## Slide 9

## Outer Belt Electrons: 1992-2002

## Mapping of the Radiation Belt

- SAMPEX: 18 August 1993

## Dynamic Radiation Belts: 1993-1995

## Acceleration by Radial Transport

- Nonrelativistically, and in a dipole,

- or

- so transport in *L* while conserving *M* will
- necessarily lead to change in energy, *W.*

## Transport in M, K:  Local Heating

## Local Heating Example:Resonant Interactions with VLF Waves

- Whistler mode chorus at dawn combined with EMIC interactions heat and isotropize particles
- Leads to transport in M, K, and L

- Summers et al. (*JGR  103*, 20487, 1998) proposed that resonant interactions with VLF waves could heat particles:

## MHD Simulations of ULF Power, 09/24/1998

- ULF power in MHD shows expected radial, frequency dependence

- Azimuthal dependence:  frequently see structure in local time

**Notes:**
Gumma
gmm

## Shear Waves and Particle Acceleration

- Limited local time: propagating waves dusk and counterpropagating waves dawn still lead to energization

## MHD Simulation of a Strong Storm

## MHD/Particle Simulations of Energetic Electron Trapping

- 60 keV test electrons, constant *M*
- Started 20 RE downtail, 15s intervals
- Evolves naturally under MHD *E *and *B* fields
- Removed from simulation at magnetopause
- Color coded by energy

## Slide 20

## Slide 21

## High-Energy Electrons: Deep-Dielectric Charging

- 3.  Influx of electrons increases to levels higher than the leakage rate

- 2.  Electrons slowly leak out of the insulator

- 1.  Electrons bury themselves in the insulator

- 4.  Electrons build up faster than they leak off

- 5.  Discharge (electrical spark) that damages or destroys the material

## Star Tracker Anomalies at GEO

*Baker et al. (1987)*

## Anomalies Due to Dielectric Charging

- Probability of discharges goes up dramatically with increasing electron fluence.

*Vampola (1977)*

## Radiation Belt Content Index

- Gives a single “Radiation Belt Electron content” Index (RBI)

- Idea introduced in Baker et al. (1999)
- Integrates over energy spectrum and 2.5 < L < 6.5

## RBI-Solar Wind Speed Comparison

- Many operational anomalies in 1994 period

- Late 1993 and early 1994 were remarkable times for VSW

## ANIK Failures: Deep-Dielectric Charging

- ANIK Anomalies

- ANIK/Intelsat
- failures in January
- 1994 occurred
- during the highest
- radiation belt
- content interval
- of the last decade

## The RBI Allows Averaging and Superposition

- Builds on idea of radiation belt “coherence”

- Annual and seasonal averaging is readily done
- Gives a true global view

*Baker et al., GRL (1999)*

## Radiation Belt Content : POLAR/SAMPEX

*Baker et al., JGR (2001)*

## October 2003 Events

## The Halloween Storm in the Heliosphere

## D. N. Baker et al.,  Nature, 16 Dec 2004

- D. N. Baker et al.,  _Nature_, 16 Dec 2004

##  Spacecraft Anomalies: October-November

-  Spacecraft Anomalies: October-November

## Day-to-Day Variation of the Radiation Belts

## Selected Days: Outer Belt Properties

## Resonant Scattering

**30.4 nm   *****EUV***

- (Courtesy of J. Goldstein )

***Plasmasphere***

**He+  15%**

## EUV Images of the Plasmasphere

***Plasmasphere***

**He+  15%**

**plasmasphere**

**Global EUV He+ Image**

## Slide 38

## Extreme Plasmasphere Erosion

## Slide 40

## D. N. Baker et al., Nature, 16 Dec 2004

- D. N. Baker et al., _Nature_, 16 Dec 2004

## Regions of Wave-Particle Interactions

## Largest Flare in Recorded History, Extremely Fast CME - Narrow Miss at Earth

- X-28 Class Flare

- SEP

- Fast CME,  2657 km/s

- Glancing Blow