# Plasma and Fusion Research

## Volume 14, 3401137 (2019)

# Regular Articles

- 1)
- National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
- 2)
- University of Tokyo, Tokyo 113-8654, Japan
- 3)
- Sokendai (The Graduate University of Advanced Studies), Toki 509-5292, Japan

### Abstract

The characteristic feature of a “horn-shaped velocity distribution” in magnetic reconnection in the presence of a guide field is investigated by means of simulation and theory. Particle simulations show that a horn-shaped velocity structure is formed in the downstream, concomitant with a ring-shaped velocity distribution studied in the preceding works. The theory which explains the motion of ions responsible for the horn-shaped structure is constructed as an extension of the basic theory for the ring-shaped structure. In the extended theory, ions are accelerated in the inflow direction by an electrostatic field in the separatrix, and thus the gyration speed of such ions in the downstream is larger than that for the basic theory. Test particle simulations confirm that some ions behave as in the extended theory and form the horn-shaped velocity structure.

### Keywords

particle simulation, magnetic reconnection, ion heating, PASMO, spherical tokamak

### Full Text

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