Empirical Constraints on O(5+) Outflows and Velocity Distributions in a Solar-Minimum Coronal Streamer

Frazin, Richard Alan

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Description

Title

Empirical Constraints on O(5+) Outflows and Velocity Distributions in a Solar-Minimum Coronal Streamer

Author(s)

Frazin, Richard Alan

Issue Date

2002

Doctoral Committee Chair(s)

Mihalas, Dimitri

Department of Study

Astronomy

Discipline

Astronomy

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Physics, Astronomy and Astrophysics

Language

eng

Abstract

As part of an effort to understand how the solar wind is energized, the so-determined electron density is used to interpret O VI lambda1032, 1037 A spectra taken with UVCS. The spectra are interpreted in terms of empirical constraints on the O5+ ion velocity distributions and outflow speeds. Four conclusions result from this work: (1) our analysis shows O5+ velocity distribution anisotropy in the streamer legs and stalk and also shows that the microscopic velocity distribution (which excludes wave motions that equally affect all charged particles) is anisotropic, where the most probable speed perpendicular to the magnetic field direction exceeds that in the parallel direction; (2) there is preferential heating of the O5+ ions over the protons in the streamer stalk and legs; (3) there is no evidence for preferential O5+ heating in the core; (4) the outflow velocity of the O5+ ions is determined at heights above 4.6 R⊙ . All results have a confidence level of at least 70%.

Graduation Semester

2002

Type of Resource

text

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