Diamagnetic structures as a basis of quasi-stationary slow solar wind

Abstract

The results presented in this review reflect the fundamentals of the modern understanding of the nature of the structure of the slow solar wind (SW) along the entire length from the Sun to the Earth's orbit. It is known that the source of the slow quasi-stationary SW on the Sun is the belt and the chains of coronal streamers The streamer belt encircles the entire Sun as a wave-like surface (skirt), representing a sequence of pairs of rays with increased brightness (plasma density) or two lines of rays located close to each other. Neutral line of the radial component of the solar global magnetic field goes along the belt between the rays of each of these pairs. The streamer belt extends in the heliosphere is as the heliospheric plasma sheet (HPS). Detailed analysis of data from Wind and IMP-8 satellites showed that HPS sections on the Earth orbit are registered as a sequence of diamagnetic tubes with high density plasma and low interplanetary magnetic field. They represent an extension of rays with increased brightness of the streamer belt near the Sun. Their angular size remains the same over the entire way from the Sun to the Earth's orbit. Each HPS diamagnetic tube has a fine internal structure on several scales, or fractality. In other words, diamagnetic tube is a set of nested diamagnetic tubes, whose angular size can vary by almost two orders of magnitude. These sequences of diamagnetic tubes that form the base of slow SW on the Earth's orbit has a more general name — diamagnetic structures (DS). In the final part of this article, a comparative analysis of several events was made, based on the results of this review. He made it possible to find out the morphology and nature of the origin of the new term “diamagnetic plasmoids” SW (local amplifications of plasma density), which appeared in several articles published during 2012–2018. The analysis carried out at the end of this article, for the first time, showed that the diamagnetic plasmoids SW are the small-scale component of the fractal diamagnetic structures of the slow SW, considered in this review.

The Compression of the Heliospheric Magnetic Structure by Interplanetary Shocks: Is the Structure at 1AU a Manifestation of Solar-Wind Turbulence or Is It Fossil Structure From the Sun?

“…This finding agrees with an earlier analysis (Borovsky and Denton, 2016) wherein the anisotropy of solar wind current sheets in the compression regions of corotating interaction regions and in the rarefaction regions of the trailing edges of high-speed streams: that analysis found no indication of current sheets isotropizing in the 10's of hours after the solar-wind plasma is compressed or rarefacted. This may support the idea that the heliospheric magnetic structure at 1 AU and its current sheets are largely fossil structure from the solar corona (e.g., Michel, 1967;Borovsky, 2008a;Huang et al, 2014;Burkholder et al, 2019;Eselevich, 2019) or remnants of a near-Sun turbulence that ceased to be active (e.g., Dobrowolny et al, 1980;Telloni et al, 2016).…”

Classification of Magnetospheric Responses to Interaction With Diamagnetic Structures of Slow Solar Wind

“…To identify its source on the Sun, we proceed from the following established and experimentally verified assumption [Eselevich et al, 2007]: a source on the solar surface should be located in the vicinity of the intersection point of the streamer belt and the ecliptic. On the synoptic map, to the streamer belt corresponds the neutral line (NL) (thick solid line NL in Figure 8, c) of the global magnetic field, which separates positive (solid curves) and negative (dashed line) field polarities in Figure 8, c. We can see that at t 0 (February 23, 1998, ~01:00 UT) the vicinity of the intersection point of NL and the ecliptic (marked with a circle) crosses the central meridian (vertical line).…”

“…On the synoptic map, to the streamer belt corresponds the neutral line (NL) (thick solid line NL in Figure 8, c) of the global magnetic field, which separates positive (solid curves) and negative (dashed line) field polarities in Figure 8, c. We can see that at t 0 (February 23, 1998, ~01:00 UT) the vicinity of the intersection point of NL and the ecliptic (marked with a circle) crosses the central meridian (vertical line). This part of NL is a source of slow SW such that the time of its arrival in Earth's orbit t Earth can be calculated from the formula [Eselevich et al, 2007] t Earth ≈ t 0 + 4.6•104/V, hr (1) where V is the velocity of the region of slow SW at 1 AU considered (km/s).…”

Classification of magnetospheric responses to interaction with diamagnetic structures of slow solar wind

“…Накопление энергии в хвосте магнитосферы происходит от двух источниковпереноса магнитной энергии пересоединения и поступающей в магнитосферу части кинетической энергии СВ. В этой связи сошлемся на работы [Lundin et al, 2003;Dmitriev, Suvorova, 2015], в которых показана возможность импульсивного прохождения плазмы СВ через дневную магнитопаузу посредством джетов. По оценкам [Dmitriev, Suvorova, 2015] средний поток плазмы в проникающих джетах составляет ~3•10 8 см -2 с -1 , что в 1.5 раза превышает поток СВ.…”

“…Пример наблюдения магнитосферного отклика второго типа, во время которого наблюдался крупномасштабный джет [Dmitriev, Suvorova, 2015], проникающий из магнитослоя в магнитосферу при контакте с ДС, показан на рис. 11, а-в.…”