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Author Livadiotis, G. ♦ Desai, M. I.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ACCURACY ♦ ALFVEN WAVES ♦ COLLISIONLESS PLASMA ♦ DATA ANALYSIS ♦ DISPERSIONS ♦ EFFICIENCY ♦ LANGMUIR FREQUENCY ♦ MAGNETIC FIELDS ♦ SOLAR WIND ♦ VELOCITY
Abstract In collisionless plasmas such as the solar wind, the coupling between plasma constituents and the embedded magnetic field occurs on various temporal and spatial scales, and is primarily responsible for the transfer of energy between waves and particles. Recently, it was shown that the transfer of energy between solar wind plasma particles and waves is governed by a new and unique relationship: the ratio between the magnetosonic energy and the plasma frequency is constant, E {sub ms}/ ω {sub pl} ∼ ℏ{sub *}. This paper examines the variability and substantial departure of this ratio from ℏ{sub *} observed at ∼1 au, which is caused by a dispersion of fast magnetosonic (FMS) waves. In contrast to the efficiently transferred energy in the fast solar wind, the lower efficiency of the slow solar wind can be caused by this dispersion, whose relation and characteristics are derived and studied. In summary, we show that (i) the ratio E {sub ms}/ ω {sub pl} transitions continuously from the slow to the fast solar wind, tending toward the constant ℏ{sub *}; (ii) the transition is more efficient for larger thermal, Alfvén, or FMS speeds; (iii) the fast solar wind is almost dispersionless, characterized by quasi-constant values of the FMS speed, while the slow wind is subject to dispersion that is less effective for larger wind or magnetosonic speeds; and (iv) the constant ℏ{sub *} is estimated with the best known precision, ℏ{sub *} ≈ (1.160 ± 0.083) × 10{sup −22} Js.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-10-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 829
Issue Number 2


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