ION HEATING BY A SPECTRUM OF OBLIQUELY PROPAGATING LOW-FREQUENCY ALFVEN WAVES

Journal Article · Sat Oct 10 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/704/1/743· OSTI ID:21367423

Quanming, Lu ^[1]; Liu, Chen ^[2]

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1. CAS Laboratory of Basic Plasma Physics, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China)
2. Institute for Fusion and Simulation, Zhejiang University, Hangzhou 310027 (China)

Ion stochastic heating by a monochromatic Alfven wave, which propagates obliquely to the background magnetic field, has been studied by Chen et al. It is shown that ions can be resonantly heated at frequencies a fraction of the ion cyclotron frequency when the wave amplitude is sufficiently large. In this paper, the monochromatic wave is extended to a spectrum of left-hand polarized Alfven waves. When the amplitude of the waves is small, the components of the ion velocity have several distinct frequencies, and their motions are quasi-periodic. However, when the amplitude of the waves is sufficiently large, the components of the ion velocity have a spectrum of continuous frequencies near the ion cyclotron frequency due to the nonlinear coupling between the Alfven waves and the ion gyromotion, and the ion motions are stochastic. Compared with the case of a monochromatic Alfven wave, the threshold of the ion stochastic heating by a spectrum of Alfven waves is much lower. Even when their frequencies are only several percent of the ion cyclotron frequency, the ions can also be stochastically heated. The relevance of this heating mechanism to solar corona is also discussed.

• OSTI ID: 21367423
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 704; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
ALFVEN WAVES
AMPLITUDES
ATMOSPHERES
CHARGED PARTICLES
CYCLOTRON FREQUENCY
ELECTROMAGNETIC RADIATION
HYDROMAGNETIC WAVES
IONS
MAGNETIC FIELDS
MAIN SEQUENCE STARS
MONOCHROMATIC RADIATION
NONLINEAR PROBLEMS
PERIODICITY
RADIATIONS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR CORONA
SOLAR WIND
SPECTRA
STARS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
STELLAR WINDS
STOCHASTIC PROCESSES
SUN
VARIATIONS
VELOCITY