Meeting 7, Sept. 12, 2006

Relationship between particle acceleration and magnetic reconnection

 

Introduction

 

The New England Space Science Consortium (NESSC) creates a cross-disciplinary, multi-institutional forum to address cutting edge research topics with a broad view toward collaboration on major opportunities in solar and space science. The consortium brings together researchers and students at Boston University (BU), the Harvard-Smithsonian Center for Astrophysics (CfA), the MIT, the Air Force Research Laboratory (AFRL) at Hanscom AFB, the University of New Hampshire (UNH), Dartmouth College, the Haystack Observatory, and Tufts University.

The consortium is a grass roots organization founded by Nathan Schwadron and Nancy Crooker at Boston University, John Raymond at CfA, Justin Kasper at MIT, Chuck Smith and Eberhard Moebius at the UNH, and Mary Hudson at Dartmouth College. The group has begun a series of informal monthly meetings in which highly relevant, interdisciplinary research topics are presented and discussed. The consortium’s broad scope has, thus far, engaged researchers from the solar, heliospheric, solar wind, magnetospheric and ionospheric communities. Continued growth in the consortium’s scientific breadth and depth will be encouraged.

The format for discussion in the New England Space Science Meetings has evolved and will continue to do so. Recent meetings have taken place in the Boston area, and often involve one to two hour discussions and lunch. This format provides a friendly atmosphere where colleagues can become more familiar with one another, forge new collaborations, raise questions, and share information and insights. The forum also presents a unique opportunity to provide students with a broad view of the field of space science. In the future, it is anticipated that one or more half-day or full-day workshops will be convened annually.

The next New England Space Science Consortium will be held on Tuesday September 12th at Boston University at 10 AM in room 500 of the Center for Arts and Sciences Building at 725 Commonwealth Ave. We will be serving pizza and salads at around noon.

The topic for discussion will be in the spirit of the generalization of fundamental processes in space plasma physics, in this case focused on the relationship between particle acceleration and magnetic reconnection.

The general topic of particle acceleration was taken up previously at the NESSC meeting at UNH. Some of the big questions that typically arise concern the interplay between stochastic acceleration versus shock acceleration. Both processes appear to go on and are, in fact, quite synergistic. Stochastic processes are thought to be responsible for the acceleration of suprathermal ions, while shocks appear to accelerate particles to the highest energies. It is interesting, however, that in quasar jets the accelerated particles are thought to be extremely rich in high-energy electrons. It also appears that many of the transient (or impulsive) solar events, thought to be associated with reconnection, are electron rich.

This opens an important connection between solar and magnetospheric energetic phenomena concerning the He3 enrichment problem. In both regimes, the enrichment of He3 is explained as the result of stochastic acceleration. However, there is an unquantified relationship between the stochastic acceleration and reconnection. Presumably, the reconnection triggers the release and subsequent dissipation of Poynting flux. Direct methods of acceleration involving parallel electric fields are also invoked to explain transient events, but the relationship between direct (or DC) electric fields and stochastic acceleration is unclear.

The topic is interesting, in part, because it touches on a broad array of sub-fields in both space physics and astrophysics. I will open the discussion with a brief intro, followed by a set of questions, in which I invite you to contribute results from research and/or your perspectives. The questions to consider are as follows