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Updated: May 26, 2026
06:42
Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
Kinetic Alfvén wave instability driven by a field-aligned current in high-β plasmas
1Purple Mountain Observatory, CAS, Nanjing 210008, China and Graduate School, CAS, Beijing 100012, China. clvslc214@pmo.ac.cn
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|December 21, 2011
Summary
This study presents a kinetic dispersion equation for plasma, revealing that field-aligned currents drive kinetic Alfvén wave instability. Increased electron drift velocity and temperature anisotropy widen the instability
Area of Science:
- Plasma Physics
- Astrophysical Plasmas
- Space Physics
Background:
- Kinetic Alfvén waves (KAWs) are crucial in space and astrophysical plasmas.
- Field-aligned currents (Birkeland currents) are significant drivers of plasma phenomena.
- Understanding KAW instability requires accounting for effects like ion-gyroradius, field-aligned currents, and temperature anisotropy.
Purpose of the Study:
- To develop a general low-frequency kinetic dispersion equation including ion-gyroradius effects.
- To investigate kinetic Alfvén wave instability driven by field-aligned currents in high-beta plasmas.
- To analyze the influence of temperature anisotropy on KAW instability.
Main Methods:
- Formulated a general low-frequency kinetic dispersion equation.
- Analyzed kinetic Alfvén wave instability driven by field-aligned electron drift.
- Investigated instability in high-beta plasma conditions.
- Performed numerical analysis of growth rates across different wave-number ranges.
- Incorporated temperature anisotropy effects into the dispersion equation.
Main Results:
- Kinetic Alfvén wave instability driven by field-aligned current exhibits a nonzero growth rate in a specific parallel wave-number range.
- The growth rate of KAW instability is maximal at approximately half the upper boundary of the parallel wave-number range.
- Instability growth rate decreases monotonically with perpendicular wave number.
- Increased electron drift velocity leads to wider growing ranges and larger growth rates.
- Temperature anisotropy significantly modifies instability conditions, widening the parametric ranges for KAW growth.
Conclusions:
- Field-aligned currents are a key driver of kinetic Alfvén wave instability in high-beta plasmas.
- Electron drift velocity and temperature anisotropy play critical roles in modulating KAW instability.
- The findings enhance understanding of active plasma phenomena in space and astrophysical environments.
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