MAGNETIC RECONNECTION TURBULENCE IN STRONG GUIDE FIELDS: BASIC PROPERTIES AND APPLICATION TO CORONAL HEATING

• Published in: The Astrophysical journal. Supplement series Vol. 213; no. 2; pp. 1 - 18
• Main Authors: Pueschel, M J, TOLD, D, Terry, P W, Jenko, F, Zweibel, E G, Zhdankin, V, Lesch, H
• Format: Journal Article
• Language: English
• Published: United States 01.08.2014
• Subjects: ACCELERATION; ANISOTROPY; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CYCLOTRON RESONANCE; Fluid dynamics; Fluid flow; HEATING RATE; MAGNETIC RECONNECTION; Nanostructure; NONLINEAR PROBLEMS; Nonlinearity; PLASMA; PLASMOIDS; SIMULATION; SOLAR CORONA; TEARING INSTABILITY; TEMPERATURE DEPENDENCE; TURBULENCE; Turbulent flow
• ISSN: 0067-0049; 1538-4365
• DOI: 10.1088/0067-0049/213/2/30

A current sheet susceptible to the tearing instability is used to drive reconnection turbulence in the presence of a strong guide field. Through nonlinear gyrokinetic simulations, the dependencies of central quantities such as the heating rate on parameters like collisionality or plasma beta are studied, revealing that linear physics tends to predict only some aspects of the quasi-saturated state, with the nonlinear cascade responsible for additional features. For the solar corona, it is demonstrated that the kinetic heating associated with this type of turbulence agrees quantitatively with observational volumetric heating rates. In the context of short particle acceleration events, the self-consistent emergence of plasmoids or flux ropes in the turbulent bath is found to be important: ubiquitously occurring merger events of these objects cause strong bursts in the heating rate, the timescale of which is consistent with nanoflare observations. Furthermore, anisotropy of the temperature fluctuations is seen to emerge, hinting at a new means of generating coronal ion temperature anisotropy in the absence of cyclotron resonances.