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MHD‐IPS analysis of relationship among solar wind density, temperature, and flow speed
Author(s) -
Hayashi Keiji,
Tokumaru Munetoshi,
Fujiki Ken'ichi
Publication year - 2016
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja022750
Subject(s) - magnetohydrodynamics , solar wind , interplanetary scintillation , physics , plasma , interplanetary magnetic field , heliosphere , computational physics , coronal mass ejection , mechanics , quantum mechanics
The solar wind properties near the Sun are a decisive factor of properties in the rest of heliosphere. As such, determining realistic plasma density and temperature near the Sun is very important in models for solar wind, specifically magnetohydrodynamics (MHD) models. We had developed a tomographic analysis to reconstruct three‐dimensional solar wind structures that satisfy line‐of‐sight‐integrated solar wind speed derived from the interplanetary scintillation (IPS) observation data and nonlinear MHD equations simultaneously. In this study, we report a new type of our IPS‐MHD tomography that seeks three‐dimensional MHD solution of solar wind, matching additionally near‐Earth and/or Ulysses in situ measurement data for each Carrington rotation period. In this new method, parameterized relation functions of plasma density and temperature at 50 R s are optimized through an iterative forward model minimizing discrepancy with the in situ measurements. Satisfying three constraints, the derived 50 R s maps of plasma quantities provide realistic observation‐based information on the state of solar wind near the Sun that cannot be well determined otherwise. The optimized plasma quantities exhibit long‐term variations over the solar cycles 21 to 24. The differences in plasma quantities derived from the optimized and original IPS‐MHD tomography exhibit correlations with the source‐surface magnetic field strength, which can in future give new quantitative constrains and requirements to models of coronal heating and acceleration.