Evaluation of the thickness of the helium current in the magnetic clouds
Abstract
On the basis of OMNI data and our catalog of large-scale solar wind phenomena (Yermolaev et al., 2009) we studied interplanetary coronal mass ejection (ICMEs) and found that maximum of helium abundance Na/Np and minimum of beta-parameter are observed in the center of magnetic clouds (MCs) and this anti-correlation is absent in non-MC ICMEs (Ejecta). These observations were interpreted as the presence of a helium electric current in magnetic clouds (Yermolaev et al., 2018). Assuming that all ICME events have the helium electric current in the center, and its registration (anti-correlation of helium and beta parameter) depends on the satellite trajectory relative to this current, it is possible to estimate the dimensions of this current relative to the dimensions of the ICME phenomena. Since the satellite trajectory can be located randomly relative to the ICME axis, we can assume that for all ~ 1600 ICME cases of our catalog in the period 1976-2017, the spacecraft trajectories are approximately parallel to the ecliptic plane and evenly spaced relative to the ICME axis. In this case, the ratio of the number of MCs and Ejecta to the total number of ICME gives an estimate of the linear size of the region with and without current, i.e. ~ 12% (187/1594) of the ICME linear size is current, and there is no current in ~ 88% of the ICME size (Yermolaev, 2019). We assume that the method used allows us to obtain an upper estimate of the size of the helium current in magnetic clouds, and the actual size may be less than 10%. This work was supported by RSF, grant 16-12-10062.
References Yermolaev, Yu. I., N. S. Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev (2009), Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Research, , Vol. 47, No. 2, pp. 81-94. Yermolaev Yu. I., I. G. Lodkina, M. Yu. Yermolaev, M. O. Riazantseva, L.S. Rakhmanova, N. L. Borodkova,Yu. S. Shugay, V. A. Slemzin, I. S. Veselovsky, D. G. Rodkin (2018), Dynamics of large-scale solar-wind streams obtained by the double superposed epoch analysis. 4. Helium abundance, http://arxiv.org/abs/1807.03579 Yermolaev Yu. I. (2019) Estimation of the size of the electric current with a high helium abundance inside the magnetic cloud, Cosmic Res., Vol. 57, No. 6, in press- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSH33B3379G
- Keywords:
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- 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7513 Coronal mass ejections;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7524 Magnetic fields;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7959 Models;
- SPACE WEATHER