Abstract / Description of output
Gradual solar energetic particle (SEP) events, where particles are often
accelerated to 10's MeV (sometimes even GeV) energies, are often
associated with CME-driven shocks. Thus, interpreting the observational
data requires understanding the structure of the shock, the acceleration
process, and the subsequent transport of energetic particles.
Theoretically, the underlying acceleration mechanism is thought to be
first-order Fermi acceleration, also known as diffusive shock
acceleration. Such a mechanism leads naturally to power-law particle
spectra, which are often observed. To connect observations with the
underlying theory, a comprehensive model that tracks particle
acceleration and transport is necessary. In this work, we describe our
model of particle acceleration and transport at CME-driven shocks and
compare the model simulation with a particular event - the April 21st,
2002 event. We chose this event for its relatively clean intensity-time
profile which is relatively free of contributions from other events. The
parent shock is thought to be driven by a CME associated with active
region 9906 (S03 W56) and was magnetically well connected to Earth.
Velocity dispersion observed during the onset of the event is a
signature of particles being accelerated near the Sun and their
subsequent transport through the interplanetary medium to 1 AU. In this
work, we have modeled the intensity-time profiles and particle energy
spectra obtained over a broad range of energies between ~
0.08~MeV/nucleon through ~ 100~MeV/nucleon from instruments on ACE,
Wind, and SAMPEX. We find excellent agreement between our model
simulations and the observations, suggesting that this approach may
provide an important step toward understanding and tracking the
influence of large SEP events in the interplanetary and geospace
environments.
Original language | English |
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Pages | 433 |
Publication status | Published - 1 Dec 2002 |
Event | American Geophysical Union, Fall Meeting 2002 - , United Kingdom Duration: 6 Dec 2002 → 10 Dec 2002 |
Conference
Conference | American Geophysical Union, Fall Meeting 2002 |
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Country/Territory | United Kingdom |
Period | 6/12/02 → 10/12/02 |
Keywords / Materials (for Non-textual outputs)
- 2118 Energetic particles
- solar
- 7513 Coronal mass ejections
- 7803 Active perturbation experiments
- 7851 Shock waves