ELECTRON ACCELERATION BY MULTI-ISLAND COALESCENCE

Journal Article · Sat May 01 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/714/1/915· OSTI ID:21448868

Oka, M; Phan, T -D; Krucker, S ^[1]; Fujimoto, M; Shinohara, I ^[2]

---

1. Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States)
2. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-0222 (Japan)

Energetic electrons of up to tens of MeV are created during explosive phenomena in the solar corona. While many theoretical models consider magnetic reconnection as a possible way of generating energetic electrons, the precise roles of magnetic reconnection during acceleration and heating of electrons still remain unclear. Here, we show from two-dimensional particle-in-cell simulations that coalescence of magnetic islands that naturally form as a consequence of tearing mode instability and associated magnetic reconnection leads to efficient energization of electrons. The key process is the secondary magnetic reconnection at the merging points, or the 'anti-reconnection', which is, in a sense, driven by the converging outflows from the initial magnetic reconnection regions. By following the trajectories of the most energetic electrons, we found a variety of different acceleration mechanisms but the energization at the anti-reconnection is found to be the most important process. We discuss possible applications to the energetic electrons observed in the solar flares. We anticipate our results to be a starting point for more sophisticated models of particle acceleration during the explosive energy release phenomena.

• OSTI ID: 21448868
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 714; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATMOSPHERES
COMPUTERIZED SIMULATION
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
GAMMA RADIATION
INSTABILITY
IONIZING RADIATIONS
LEPTONS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC ISLANDS
MAGNETIC RECONNECTION
MAIN SEQUENCE STARS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
RADIATIONS
SIMULATION
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR CORONA
SOLAR FLARES
STARS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
STELLAR FLARES
SUN
TAIL ELECTRONS
TEARING INSTABILITY
TWO-DIMENSIONAL CALCULATIONS