A KINETIC MODEL OF SOLAR WIND GENERATION BY OBLIQUE ION-CYCLOTRON WAVES

Journal Article · Wed Apr 20 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/731/2/88· OSTI ID:21574722

Isenberg, Philip A; Vasquez, Bernard J ^[1]

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1. Institute for the Study of Earth, Oceans and Space and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)

The fast solar wind is generated by extended perpendicular ion heating in coronal holes, but the kinetic mechanism responsible for this heating has not been determined. One long-standing possibility is the resonant-cyclotron dissipation of ion-cyclotron waves, replenished from a turbulent cascade of interacting counter-propagating Alfven waves. We present results of a kinetic model for proton heating by the quasilinear resonant-cyclotron wave-particle interaction in a coronal hole. The resonant wave spectrum is taken as a power law in wavenumber, uniformly distributed in propagation direction between 0 deg. and 60 deg. with respect to the large-scale radial magnetic field. We obtain the steady-state solution of the kinetic guiding-center equation for the proton distribution in an expanding coronal hole, including the effects of large-scale forces of gravity, charge-separation electric field, Alfven wave ponderomotive force, and mirror force, along with the small-scale scattering from the wave dissipation. We find that plausible wave intensities can yield reasonable flow speeds and temperatures in the heliocentric radial range between 2 and 6 solar radii. We address the claim in earlier work that dissipation of parallel-propagating ion-cyclotron waves cannot provide enough acceleration and show that claim to be incorrect. We find that the combined action of the large-scale forces and the resonant-cyclotron scattering produces proton distribution functions with a characteristic structure: compressed in the sunward half of velocity space with a high-density shell separate from the origin, and relatively expanded in the anti-sunward half of velocity space. We suggest that qualitatively similar proton distributions would result from the kinetic evolution of any sufficiently effective perpendicular heating mechanism operating in an expanding coronal hole.

• OSTI ID: 21574722
• Journal Information: Astrophysical Journal, Vol. 731, Issue 2; Other Information: DOI: 10.1088/0004-637X/731/2/88; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ALFVEN WAVES
DISTRIBUTION FUNCTIONS
HEATING
ION PLASMA WAVES
PROTONS
SOLAR CORONA
SOLAR WIND
ATMOSPHERES
BARYONS
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HADRONS
HYDROMAGNETIC WAVES
ION WAVES
NUCLEONS
PLASMA WAVES
SOLAR ACTIVITY
SOLAR ATMOSPHERE
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
STELLAR WINDS