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

Abstract

We propose a possible classification of the responses of the magnetosphere to the interaction with diamagnetic structures (DS), which form the basis of the slow solar wind. The main determinants of the classification are the value and orientation of the vertical component Bz of the interplanetary magnetic field (IMF) and the solar wind density N. We have identified three types of magnetospheric responses. Type 1 has two subtypes whose main difference is the presence or absence of auroras on the day side of the magnetosphere. Within an hour before DS arrival, Bz has a positive value (up to 12 nT) or fluctuates about 0 in the range from –1 to +1 nT. For both subtypes, the duration of substorm disturbances approximately coincides with the duration of DS, and their intensity does not exceed AE~500 nT. Type 2 is characterized by the fact that before the contact with DS positive IMF Bz (0–10 nT) is recorded for an hour, and at the interface of DS a rapid (≤2 min) change in the orientation of the IMF vertical component from north to south occurs. For type 3, Bz within an hour before the contact with DS is negative (from –10 to 0 nT).
 We address the problem of DS energy transfer to the magnetosphere.

Correspondence of a global isolated substorm to the McPherron statistical model

“…Our results and the results of studies of the DSmagnetosphere interaction reported in [Parkhomov et al, 2015[Parkhomov et al, , 2020[Parkhomov et al, , 2021 can be explained by the model [McPherron et al, 1986] presented in Figure 9, a. The model was built on the basis of a large statistics of observations of global isolated substorms, which were triggered by a sharp change in the long-term (~2 hrs) northward orientation of IMF Bz to the southward.…”

“…At 09:40 UT there was a density jump to N≈13 cm -3 ; at 10:13 UT the density increased to ~21 cm -3 , and at 10:40 UT it reached its maximum value of 33 cm -3 . Specifically, the IMF modulus varies in antiphase with the density (r=-0.74), which, as noted above, is an indication of the diamagnetic structure [Parkhomov et al, 2018].…”

“…In [Lemaire, Roth, 1981;Pneuman, 1983;Karlsson et al, 2015], the concept of plasmoids in SW was introduced. Such structures are defined in [Eselevich, Eselevich, 2005;Parkhomov et al, 2018] as plasma diamagnetic structures (DS). Collision of slow-SW diamagnetic structures with the magnetosphere can cause substorm-like magnetospheric disturbances, in particular so-called sawtooth substorms.…”

“…Collision of slow-SW diamagnetic structures with the magnetosphere can cause substorm-like magnetospheric disturbances, in particular so-called sawtooth substorms. In [Eselevich, Eselevich, 2005;Parkhomov et al, 2018;Parkhomov et al, 2015Parkhomov et al, , 2020, the diamagnetic structures that are seen near the Sun as higher brightness rays are shown to form the basis of slow quasi-stationary SW in Earth's orbit. Solar sources of slow quasi-stationary SW are the streamer belt [Svalgaard et al, 1974;Eselevich et al, 1999] and streamer chains [Eselevich et al, 1999] or pseudostreamers [Wang et al, 2007].…”

Solar wind magnetic holes can cross the bow shock and enter the magnetosheath

“…Sperveslage et al, 2000;Winterhalter et al, 1994) or mirror mode structures created when the plasma is marginally mirror unstable (Karlsson et al, 2021). Other theories are that the magnetic holes are the result of non-linear interaction of Alfvén waves with the solar wind plasma (Buti et al, 2001;Tsurutani, Dasgupta, et al, 2002;Tsurutani, Galvan, et al, 2002), emerging coherent structures in solar wind turbulence (Perrone et al, 2016;Roytershteyn et al, 2015), or diamagnetic structures formed in the solar corona (Parkhomov et al, 2019).…”