Kinetic Equilibrium of Dipolarization Fronts

Abstract:

Compression in plasma perpendicular to the magnetic field produces a boundary layer with pressure gradient in which the plasma characteristics undergo a significant change. When the layer width reduces towards an ion gyro-diameter an ambi-polar potential is generated across the magnetic field and intensifies with narrowing layer width. The transverse electric field makes the particle distribution non-gyrotropic and causes temperature anisotropy. In a dipolar geometry, variation in the magnetic field and the plasma parameters along the field lines results in a potential difference along the magnetic field. The consequent parallel electric field can accelerate ions and electrons to form inhomogeneous beams and cause pressure anisotropy. Localized transverse electric fields and parallel inhomogeneous beams or flows are known sources for broadband velocity shear driven waves. Relevance to the structure and dynamics of dipolarization fronts is discussed.

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