Particle acceleration at coronal mass ejection–driven interplanetary shocks and the Earth's bow shock

Abstract

[1] Particle acceleration in space plasmas, particularly at collisionless shocks, remains a fundamental yet poorly understood problem in space physics. The most important questions that need to be addressed include (1) where are the particles accelerated, (2) what source material is available for acceleration, (3) what mechanisms are responsible for injecting and accelerating the particles, and (4) how are the particle properties modified during their propagation from the acceleration sites to the observation point? Answering these questions will enable further development of the theoretical framework and models that will facilitate quantitative predictions of key properties of the accelerated particles. In this paper, we review recent observations associated with two distinct but widely studied energetic ion populations: (1) solar energetic particles associated with coronal mass ejection-driven interplanetary shocks and (2) energetic ions observed upstream of the Earth's bow shock. We review the common theoretical concepts and physical processes that are believed to be responsible for accelerating particles at these two types of collisionless shocks, emphasizing the commonalities between these distinct structures and their associated particle populations.Citation: Desai, M. I., and D. Burgess (2008), Particle acceleration at coronal mass ejection -driven interplanetary shocks and the Earth's bow shock,

Acceleration of Low-Energy Ions at Parallel Shocks With a Focused Transport Model

“…However, the sources of the energetic particles in the heliosphere are usually regarded as low-energy thermal or suprathermal ions of solar and interplanetary origin (e.g., Zank et al 2001;Mason et al 2005Mason et al , 2012Desai et al 2003Desai et al , 2006Desai & Burgess 2008). For example, there is strong evidence that a small portion of thermal and suprathermal particles from hot corona material or remnants of previous solar energetic particle (SEP) events serve as the source of large SEP events (Desai et al 2006).…”

Heavy ion acceleration at parallel shocks

“…To solve numerically we have chosen the number density of alpha particles to be 5% of the proton density, that corresponds to mass-loading parameter being equal to 0.2. This He/H abundance ratio is typical for the fast solar wind streams (Gloeckler et al, 1994;Torsti et al, 2001;Desai and Burgess, 2008).…”

Solar Wind Laws Valid for any Phase of a Solar Cycle

“…Even though considerable successes have been achieved in developing the "foreshock" theory, many questions (the complete list is given in (Desai and Burgess, 2008) are still unanswered. Over the last thirty years, many papers have been written on impulsive and gradual events of solar energetic particles (SEP) (e.g., Cliver, et al, 1982;Kahler, et al, 1984;Mason et al, 1984;Cane et al, 1986, etc.…”