Formation of Multiple Current Sheets in the Heliospheric Plasma Sheet
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ation of Multiple Current Sheets in the Heliospheric Plasma Sheet E. V. Maiewskia, c, *, H. V. Malovab, c, **, R. A. Kislovc, d, V. Yu. Popova, c, e, A. A. Petrukovichc, O. V. Khabarovac, d, and L. M. Zelenyic aNational
Research University Higher School of Economics, Moscow, 101000 Russia Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, 119234 Russia c Space Research Institute, Russian Academy of Sciences, Moscow, 117997 Russia d Pushkov Institute of Terrestrial Magnetism, the Ionosphere, and Radio Wave Propagation, Russian Academy of Sciences, Moscow, 108840 Russia e Physical Faculty, Moscow State University, Moscow, 119991 Russia *e-mail: [email protected] **e-mail: [email protected] b
Received February 25, 2020; revised May 6, 2020; accepted May 29, 2020
Abstract—When spacecraft cross the heliospheric plasma sheet (HPS) that separates large-scale magnetic sectors of opposite directions in the solar wind, multiple rapid fluctuations in the sign of the magnetic radial component are often observed. These fluctuations indicate the change of the sign of the azimuth electric current density within the HPS. Possible mechanisms of formation of the multilayered current structure of the HPS are proposed. Within the context of a stationary magnetohydrodynamic solar wind model, we test one of the most popular hypotheses regarding an extension of multiple current sheets from the streamer belt oriented along the neutral line of the solar magnetic field into the solar wind. Properties of self-consistent distributions of the solar wind key characteristics are investigated as function of the fine structure of streamers. The results show that both single and multiple streamers can be the source of the set of a multilayered structure with alternating azimuthal currents. The significance of the results for the interpretation of solar wind data is discussed. DOI: 10.1134/S0010952520060076
1. INTRODUCTION Long-term studies of the solar wind (SW) using space vehicles have shown that the SW is a complex magnetoplasma structure with two characteristic time scales of variations: the first scale is on the order of days (weeks) and more, when the SW can be considered quasi-stationary; the second is on the order of minutes or hours, when sporadic, rapid processes occur in the SW [1–3]. Examples of large-scale quasistationary structures in the SW are the heliospheric plasma sheet (HPS), with a thickness of 2–2.5 RS ( RS ≈ 7 × 105 km is the radius of the Sun), which is located in the plane of the solar equator, and the embedded heliospheric current sheet (HCS), which is approximately 104 km thick [4–6]. According to modern views, the HCS is a relatively thin disk-shaped current surface, which separates oppositely directed magnetic fluxes emanating from the Sun. The natural curvature of the HPS surface (and, therefore, the embedded HCS) with respect to the ecliptic plane leads to the fact that the Earth, at a distance of 1 AU
(1 AU ≈ 215 RS is astronomical unit), periodically crosses the boundaries of magnetic secto
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