Particle Acceleration in an Evolving Network of Unstable Current Sheets

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

37 pages, 10 figures, one of them in color; in press at ApJ (2004)

Scientific paper

10.1086/386364

We study the acceleration of electrons and protons interacting with localized, multiple, small-scale dissipation regions inside an evolving, turbulent active region. The dissipation regions are Unstable Current Sheets (UCS), and in their ensemble they form a complex, fractal, evolving network of acceleration centers. Acceleration and energy dissipation are thus assumed to be fragmented. A large-scale magnetic topology provides the connectivity between the UCS and determines in this way the degree of possible multiple acceleration. The particles travel along the magnetic field freely without loosing or gaining energy, till they reach a UCS. In a UCS, a variety of acceleration mechanisms are active, with the end-result that the particles depart with a new momentum. The stochastic acceleration process is represented in the form of Continuous Time Random Walk (CTRW), which allows to estimate the evolution of the energy distribution of the particles. It is found that under certain conditions electrons are heated and accelerated to energies above 1 MeV in much less than a second. Hard X-ray (HXR) and microwave spectra are calculated from the electrons' energy distributions, and they are found to be compatible with the observations. Ions (protons) are also heated and accelerated, reaching energies up to 10 MeV almost simultaneously with the electrons. The diffusion of the particles inside the active region is extremely fast (anomalous super-diffusion). Although our approach does not provide insight into the details of the specific acceleration mechanisms involved, its benefits are that it relates acceleration to the energy release, and it well describes the stochastic nature of the acceleration process.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Particle Acceleration in an Evolving Network of Unstable Current Sheets does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Particle Acceleration in an Evolving Network of Unstable Current Sheets, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Particle Acceleration in an Evolving Network of Unstable Current Sheets will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-293500

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.