Observation of the Solar-Wind Turbulence Near the Sun

Citation

Callahan, Philip Sidney (1974) Observation of the Solar-Wind Turbulence Near the Sun. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/9ZFM-K287. https://resolver.caltech.edu/CaltechETD:etd-10282005-130203

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The solar-wind turbulence near the sun is investigated with data obtained near the superior conjunctions of Mariners 6, 7, and 9. The data are time histories of the change in the electron columnar content between the earth and spacecraft. The data were obtained with a group-phase technique which is sensitive only to the change in the columnar content. The measurement technique is discussed. The theory of power spectra is outlined. The relationship between the temporal power spectrum of the columnar content data and the comoving wave-number spectrum of the solar wind is derived. It is found that comoving spectrum is well represented by a power-law [...] of index [...]= 3.9 [...] 0.2. Comparison of the overall average spectral amplitude near the sun [...] to that near 1 a.u. shows that the turbulence declines with heliocentric distance as [...], ignoring time variations. In the region near the sun (0.07 [...] r [...] 0.22 a.u.) [...] declines more slowly. It is suggested that there is a region of enhanced turbulence near the sun. The Mariner 9 spectral amplitudes correlate with Zurich sunspot number. The data are used to investigate the relationship between McMath calcium plage regions and density enhancements intersecting the line of sight. The relationship of the present observations to theories of solar wind heating and to interplanetary scintillation observations is discussed.

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