Effect of Electron Pressure on the Grad–Shafranov Reconstruction of Interplanetary Coronal Mass Ejections
| Autor: | Christian Möstl, R. P. Lepping, Vladimir A. Osherovich, Charlie J. Farrugia, K. W. Ogilvie, Qiang Hu, Adam Szabo |
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| Rok vydání: | 2013 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Proton Astronomy and Astrophysics Atmospheric-pressure plasma Plasma Electron 01 natural sciences Magnetic flux 13. Climate action Space and Planetary Science Physics::Space Physics 0103 physical sciences Coronal mass ejection Electron temperature Magnetic pressure Atomic physics 010303 astronomy & astrophysics 0105 earth and related environmental sciences |
| Zdroj: | Solar Physics |
| ISSN: | 1573-093X 0038-0938 |
| DOI: | 10.1007/s11207-013-0259-y |
| Popis: | We investigate the effect of electron pressure on the Grad–Shafranov (GS) reconstruction of Interplanetary Coronal Mass Ejection (ICME) structures. The GS method uses in situ magnetic field and plasma measurements to solve for a magnetohydrostatic quasi-equilibrium state of space plasmas. For some events, a magnetic flux-rope structure embedded within the ICME can be reconstructed. The electron temperature contributes directly to the calculation of the total plasma pressure, and in ICMEs its contribution often substantially exceeds that of proton temperature. We selected ICME events observed with the Wind spacecraft at 1 AU and applied the GS reconstruction method to each event for cases with and without electron temperature measurements. We sorted them according to the proton plasma β (the ratio of proton plasma pressure to magnetic pressure) and the electron-to-proton temperature ratio. We present case studies of three representative events, show the cross sections of GS reconstructed flux-rope structure, and discuss the electron pressure contribution to key quantities in the numerical reconstruction procedure. We summarize and compare the geometrical and physical parameters derived from the GS reconstruction results for cases with and without electron temperature contribution. We conclude that overall the electron pressure effect on the GS reconstruction results contributes to a 10 – 20 % discrepancy in some key physical quantities, such as the magnetic flux content of the ICME flux rope observed at 1 AU. |
| Databáze: | OpenAIRE |
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