Special Issue "Solar Wind Structures and Phenomena: Origins, Properties, Geoeffectiveness, and Prediction"

A special issue of Universe (ISSN 2218-1997). This special issue belongs to the section "Solar System".

Deadline for manuscript submissions: closed (25 September 2022) | Viewed by 6756

Special Issue Editors

Dr. Yuri Yermolaev
E-Mail Website
Guest Editor
Space Research Institute, Russian Academy of Sciences, 117997 Moscow, Russia
Interests: solar wind structures at various scales; space weather
Dr. Vladimir A. Slemzin
E-Mail Website1 Website2 Website3
Guest Editor
P.N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow, Russia
Interests: solar physics; optics; spectroscopy; space research
Dr. Volker Bothmer
E-Mail Website
Guest Editor
Institute for Astrophysics, Georg-August-University of Göttingen, 37077 Göttingen, Germany
Interests: solar and heliospheric physics; space plasma physics; solar energetic particles; cosmic rays; physics of the Earth’s magnetosphere; science and technology studies to develop future space missions and instruments

Special Issue Information

Dear Colleagues,

One of the fundamental properties of the heliosphere is the presence of solar wind structures and phenomena on a wide range of scales, and solar wind is an open system with free energy transfer from large to small scales. First, large-scale solar wind structures (such as ICMEs and CIRs with sizes at 1 AU more than 106 km) are born at the Sun and do not have enough time to modify significantly during the path to the Earth and thus contain information on structure and processes at the Sun. Second, small-scale solar wind phenomena (with sizes less than 104 km) are induced locally and give the opportunity to explore processes in plasmas where no collisions occurs between charged particles and walls of peculiar space laboratory. Finally, solar wind is the important agent which transfers disturbances from the Sun to the Earth’s magnetosphere and generates disturbances in the magnetosphere-ionosphere system, i.e., sudden modifications in the solar wind cause various space weather phenomena. The Special Issue will be devoted to recent progress in the physics of solar wind and heliospheric media, including results of actual missions providing new insights into the structure and origins of solar wind and solar corona, such as the Parker Solar Probe and Solar Orbiter.

We invite contributions on all aspects of solar, helio-, and magnetosphere physics, starting from the solar corona, into solar wind, including the inner heliosphere, the Earth’s orbit, and beyond.

Dr. Yuri Yermolaev
Dr. Vladimir A. Slemzin
Dr. Volker Bothmer
Guest Editors

Manuscript Submission Information

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Keywords

  • solar wind structure
  • magnetic cloud
  • sheath
  • CIR/SIR
  • discontinues
  • turbulence
  • origin
  • propagation and evolution
  • coronal mass ejections
  • solar wind prediction

Published Papers (11 papers)

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Editorial

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Editorial
Editorial to the Special Issue “Solar Wind Structures and Phenomena: Origins, Properties, Geoeffectiveness, and Prediction”
Universe 2023, 9(1), 53; https://doi.org/10.3390/universe9010053 - 12 Jan 2023
Viewed by 271
Abstract
The heliosphere is filled with solar wind, which is formed due to the expansion of the plasma of hot solar corona [...] Full article

Research

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Article
Coronal Field Geometry and Solar Wind Speed
Universe 2022, 8(12), 646; https://doi.org/10.3390/universe8120646 - 05 Dec 2022
Cited by 1 | Viewed by 466
Abstract
The Wang–Sheeley–Arge (WSA) solar wind (SW) model is based on the idea that weakly expanding coronal magnetic field tubes are associated with sources of fast SWs and vice versa. A parameter called the “flux tube expansion” (FTE) is used to determine the degree [...] Read more.
The Wang–Sheeley–Arge (WSA) solar wind (SW) model is based on the idea that weakly expanding coronal magnetic field tubes are associated with sources of fast SWs and vice versa. A parameter called the “flux tube expansion” (FTE) is used to determine the degree of expansion of magnetic tubes. The FTE is calculated based on the coronal magnetic field model, usually in the potential approximation. The second input parameter for the WSA model is the great circle distance from the base of the open magnetic field line in the photosphere to the boundary of the corresponding coronal hole (DCHB). These two coronal magnetic field parameters are related by an empirical relationship with the solar wind velocity near the Sun. The WSA model has shortcomings and does not fully explain the solar wind formation mechanisms. In the present work, we model various coronal magnetic field parameters in the potential-field source-surface (PFSS) approximation from a long series of magnetographic observations: the Solar Telescope-magnetograph for Operative Prognoses (STOP) (Kislovodsk Mountain Astronomical Station), the Helioseismic and magnetic imager (SDO/HMI), and data from the Wilcox Solar Observatory (WSO). Our main goal is to identify correlations between the coronal magnetic field parameters and the observed SW velocity in order to use them for modeling SW. We found that the SW velocity correlates relatively well with some geometric properties of the magnetic tubes, including the force line length, the latitude of the force line footpoints, and the DCHB. We propose a formula for calculating the SW velocity based on these parameters. The presented relationship does not use FTE and showed a better correlation with observations compared to the WSA model. Full article
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Article
Large-Scale Solar Wind Phenomena Affecting the Turbulent Cascade Evolution behind the Quasi-Perpendicular Bow Shock
Universe 2022, 8(12), 611; https://doi.org/10.3390/universe8120611 - 23 Nov 2022
Cited by 1 | Viewed by 606
Abstract
The Earth’s magnetosphere is permanently influenced by the solar wind. When supersonic and superalfvenic plasma flow interacts with the magnetosphere, the magnetosheath region is formed, which is filled with shocked turbulent plasma. Varying SW parameters influence the mechanisms of formation of this boundary [...] Read more.
The Earth’s magnetosphere is permanently influenced by the solar wind. When supersonic and superalfvenic plasma flow interacts with the magnetosphere, the magnetosheath region is formed, which is filled with shocked turbulent plasma. Varying SW parameters influence the mechanisms of formation of this boundary layer, including the dynamics of turbulence behind the bow shock. The effect of the solar wind on the development of turbulence in the magnetosheath was demonstrated recently based on broad statistics of spacecraft measurements. The present study considers the multipoint observations of turbulent fluctuations in the solar wind, in the dayside magnetosheath and at the flanks, to analyze the evolution of the turbulent cascade while the solar wind plasma enters the magnetosheath. Observations of the magnetosheath behind the quasi-perpendicular bow shock are analyzed to exclude the influence of the bow shock topology from consideration. Three basic types of solar wind flows are considered: slow undisturbed solar wind, compressed regions, and interplanetary manifestations of coronal mass ejections. The results show surviving Kolmogorov scaling behind the bow shock for steady solar wind flow and amplification of the compressive fluctuations at the kinetic scales at the magnetosheath flanks for the solar wind associated with compressed plasma streams. During interplanetary manifestations of the coronal mass ejection, the spectra in the dayside magnetosheath substantially deviate from those observed in the solar wind (including the absence of Kolmogorov scaling and steepening at the kinetic scales) and restore at the flanks. Full article
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Article
Modeling of Solar Wind Disturbances Associated with Coronal Mass Ejections and Verification of the Forecast Results
Universe 2022, 8(11), 565; https://doi.org/10.3390/universe8110565 - 27 Oct 2022
Cited by 1 | Viewed by 551
Abstract
Solar wind (SW) disturbances associated with coronal mass ejections (CMEs) cause significant geomagnetic storms, which may lead to the malfunction or damage of sensitive on-ground and space-based critical infrastructure. CMEs are formed in the solar corona, and then propagate to the Earth through [...] Read more.
Solar wind (SW) disturbances associated with coronal mass ejections (CMEs) cause significant geomagnetic storms, which may lead to the malfunction or damage of sensitive on-ground and space-based critical infrastructure. CMEs are formed in the solar corona, and then propagate to the Earth through the heliosphere as Interplanetary CME (ICME) structures. We describe the main principles in development with the online, semi-empirical system known as the Space Monitoring Data Center (SMDC) of the Moscow State University, which forecasts arrival of ICMEs to Earth. The initial parameters of CMEs (speeds, startup times, location of the source) are determined using data from publicly available catalogs based on solar images from space telescopes and coronagraphs. After selecting the events directed to Earth, the expected arrival time and speed of ICMEs at the L1 point are defined using the Drag-Based model (DBM), which describes propagation of CMEs through the heliosphere under interaction with the modeled quasi-stationary SW. We present the test results of the ICME forecast in the falling phase of Cycle 24 obtained with the basic version of SMDC in comparison with results of other models, its optimization and estimations of the confidence intervals, and probabilities of a successful forecast. Full article
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Article
Helium Abundance Decrease in ICMEs in 23–24 Solar Cycles
Universe 2022, 8(11), 557; https://doi.org/10.3390/universe8110557 - 26 Oct 2022
Cited by 1 | Viewed by 395
Abstract
Based on the OMNI database, the influence of the solar activity decrease in solar cycles (SCs) 23–24 on the behavior of the relative helium ions abundance Nα/Np inside interplanetary coronal mass ejections (ICMEs) is investigated. The dependences of the helium [...] Read more.
Based on the OMNI database, the influence of the solar activity decrease in solar cycles (SCs) 23–24 on the behavior of the relative helium ions abundance Nα/Np inside interplanetary coronal mass ejections (ICMEs) is investigated. The dependences of the helium abundance on the plasma and interplanetary magnetic field parameters in the epoch of high solar activity (SCs 21–22) and the epoch of low activity (SCs 23–24) are compared. It is shown that Nα/Np significantly decreased in SCs 23–24 compared to SCs 21–22. The general trends of the dependences have not changed with the change of epoch, but the helium abundance dependences on some parameters (for example, the magnitude of the interplanetary magnetic field) have become weaker in the epoch of low activity than they were in the epoch of high activity. In addition, the dependence of the helium abundance on the distance from spacecraft to the ICME axis was revealed; the clearest dependence is observed in magnetic clouds. The Nα/Np maximum is measured at the minimum distance, which confirms the hypothesis of the existence of a helium-enriched electric current inside an ICME. Full article
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Article
Dynamics of He++ Ions at Interplanetary and Earth’s Bow Shocks
Universe 2022, 8(10), 516; https://doi.org/10.3390/universe8100516 - 01 Oct 2022
Cited by 1 | Viewed by 466
Abstract
Experimental investigations of the fine plasma structure of interplanetary shocks are extremely difficult to conduct due to their small thickness and high speed relative to the spacecraft. We studied the variations in the parameters of twice-ionized helium ions (4He++ ions or α-particles) [...] Read more.
Experimental investigations of the fine plasma structure of interplanetary shocks are extremely difficult to conduct due to their small thickness and high speed relative to the spacecraft. We studied the variations in the parameters of twice-ionized helium ions (4He++ ions or α-particles) in the solar wind plasma during the passage of interplanetary shocks and Earth’s bow shock. We used data with high time resolution gathered by the BMSW (Bright Monitor of Solar Wind) instrument installed on the SPEKTR-R satellite, which operated between August 2011 and 2019. The MHD parameters of He++ ions (the bulk velocity Vα, temperature Tα, absolute density Nα, and helium abundance Nα/Np) are analyzed for 20 interplanetary shocks and compared with similar parameters for 25 Earth bow shock crossings. Measurements from the WIND, Cluster, and THEMIS satellites were also analyzed. The correlations in the changes in helium abundance Nα/Np with the parameters βi, θBn, and MMS were investigated. The following correlation between Nα/Np and the angle θBn was found: the lower the value of θBn, the greater the drop in helium abundance (Nα/Np) falls behind the IP shock front. For Earth’s bow shock crossings, we found a significant increase in the helium abundance (Nα/Np) in quasi-perpendicular events. Full article
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Communication
Peculiarities of the Heliospheric State and the Solar-Wind/Magnetosphere Coupling in the Era of Weakened Solar Activity
Universe 2022, 8(10), 495; https://doi.org/10.3390/universe8100495 - 22 Sep 2022
Cited by 1 | Viewed by 561
Abstract
Based on the data of the solar wind (SW) measurements of the OMNI database for the period 1976–2019, we investigate the behavior of SW types, as well as plasma and interplanetary magnetic field (IMF) parameters, for 21–24 solar cycles (SCs). Our analysis shows [...] Read more.
Based on the data of the solar wind (SW) measurements of the OMNI database for the period 1976–2019, we investigate the behavior of SW types, as well as plasma and interplanetary magnetic field (IMF) parameters, for 21–24 solar cycles (SCs). Our analysis shows that with the beginning of the period of low solar activity (SC 23), the number of all types of disturbed events in the interplanetary medium decreased, but the proportion of magnetic storms initiated by CIR increased. In addition, a change in the nature of SW interaction with the magnetosphere could occur due to a decrease in the density, temperature, and IMF of solar wind. Full article
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Article
Dynamics of Large-Scale Solar-Wind Streams Obtained by the Double Superposed Epoch Analysis: 5. Influence of the Solar Activity Decrease
Universe 2022, 8(9), 472; https://doi.org/10.3390/universe8090472 - 09 Sep 2022
Cited by 2 | Viewed by 612
Abstract
In solar cycles 23–24, solar activity noticeably decreased and, as a result, solar wind parameters decreased. Based on the measurements of the OMNI base for the period 1976–2019, the time profiles of the main solar wind parameters and magnetospheric indices for the main [...] Read more.
In solar cycles 23–24, solar activity noticeably decreased and, as a result, solar wind parameters decreased. Based on the measurements of the OMNI base for the period 1976–2019, the time profiles of the main solar wind parameters and magnetospheric indices for the main interplanetary drivers of magnetospheric disturbances (solar wind types CIR. Sheath, ejecta and MC) are studied using the double superposed epoch method. The main task of the research is to compare time profiles for the epoch of high solar activity at 21–22 SC and the epoch of low activity at 23–24 SC. The following results were obtained. (1) The analysis did not show a statistically significant change in driver durations during the epoch of minimum. (2) The time profiles of all parameters for all types of SW in the epoch of low activity have the same shape as in the epoch of high activity, but locate at lower values of the parameters. (3) In CIR events, the longitude angle of the solar wind flow has a characteristic S shape; but in the epoch of low activity, it varies in a larger range than in the previous epoch. Full article
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Article
Electron Temperature Anisotropy Effects on Alpha/Proton Instability in the Solar Wind
Universe 2022, 8(9), 466; https://doi.org/10.3390/universe8090466 - 07 Sep 2022
Cited by 1 | Viewed by 538
Abstract
In situ recordings by the solar Wind spacecraft reveal the ubiquitousness of alpha particles, whose drift velocities to the background proton vα are generally less than or equal to the local Alfvén velocity vA. The alpha beam instability plays a [...] Read more.
In situ recordings by the solar Wind spacecraft reveal the ubiquitousness of alpha particles, whose drift velocities to the background proton vα are generally less than or equal to the local Alfvén velocity vA. The alpha beam instability plays a significant role in the alpha beam deceleration in the solar wind; nonetheless, the detailed mechanism of deceleration remains unclear. By using the linear Vlasov equation of the PDRK/B0 solver, the present work investigates the kinetic instability caused by both the alpha beam and the electron temperature anisotropy in the solar wind and assesses the effects of the electron temperature anisotropy on such instability. The results show that both anisotropic electrons and alpha beams lead to the excitation of several plasma waves, and the wave frequency, growth rate, and polarization properties are sensitive to the electron temperature anisotropy (Te/Te), the parallel electron beta (βe), and the alpha beam drift velocity (vα/vA). With an excess parallel temperature Te/Te<1, the parallel magnetosonic/whistler (PM/W), parallel Alfvén wave (PAW), and oblique Alfvén/ion cyclotron (OA/IC) instabilities could be generated, while for an excess perpendicular temperature Te/Te>1, the PM/W, OA/IC, parallel whistler (PW), and kinetic Alfvén wave (KAW) instabilities could grow. In the region of Te/Te<1, the thresholds of the PM/W, PAW, and OA/IC instabilities extend to lower drift velocity vα/vA. In the region of Te/Te>1, the thresholds of the PM/W and OA/IC instabilities increase, while those of the PW and KAW instabilities are shifted to lower vα/vA. The current study presents a comprehensive overview for alpha beam instabilities that limit the alpha beam drift velocity in the solar wind. Full article
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Article
Properties of the Geomagnetic Storm Main Phase and the Corresponding Solar Wind Parameters on 21–22 October 1999
Universe 2022, 8(7), 346; https://doi.org/10.3390/universe8070346 - 23 Jun 2022
Cited by 3 | Viewed by 682
Abstract
We use the SYM-H index to indicate the ring current index. We find that there were two periods during which the SYM-H index decreased quickly during the main phase of the geomagnetic storm on 21–22 October 1999. The first period from 11:44 p.m. [...] Read more.
We use the SYM-H index to indicate the ring current index. We find that there were two periods during which the SYM-H index decreased quickly during the main phase of the geomagnetic storm on 21–22 October 1999. The first period from 11:44 p.m. UT on 21 October 1999 to 1:35 a.m. UT on 22 October 1999 is defined as step 1. Another period from 3:36 a.m. UT to 5:49 a.m. UT on 22 October 1999 is defined as step 3. The durations of step 1 and step 3 are defined as Δt1 and Δt3, respectively. The variation of the pressure-corrected SYM-H index during step 1 and step 3 are defined as ΔSYMHob1 and ΔSYMHob3, respectively. The interplanetary (IP) sources responsible for ΔSYMHob1 and ΔSYMHob3 are determined as the solar wind during period 1 and period 3, respectively. We find that the largest southward component of the interplanetary magnetic field (Bsmax) during period 3 was larger than that during period 1, and the largest solar wind dawn-to-dusk electric field (Eymax) during period 3 was also larger than that during period 1. We also find that the time integral of Ey during period 3 was much larger than that during period 1. However, we find that |ΔSYMHob1| was larger than |ΔSYMHob3|, and |ΔSYMHob1/Δt1| was larger than |ΔSYMHob3/Δt3|, indicating that the geomagnetic activity intensity during a period does not depend on Bsmax or Eymax, nor does it depend on the time integral of Ey. What is the reason for this? We find that the solar wind dynamic pressure during period 1 was larger than that during period 3, indicating that the geomagnetic storm intensity during a period not only depends on the solar wind speed and Bs, but it also depends on the solar wind dynamic pressure. The magnetosphere took 4 min to respond to the IP shock. When the z-component of the interplanetary magnetic field (IMF) turned from northward to southward, the response time of the SYM-H index to the southward component of the IMF was 21 min. Full article
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Article
Ulysses Flyby in the Heliosphere: Comparison of the Solar Wind Model with Observational Data
Universe 2022, 8(6), 324; https://doi.org/10.3390/universe8060324 - 10 Jun 2022
Cited by 1 | Viewed by 883
Abstract
A model capable of reproducing a set of solar wind parameters along the virtual spacecraft orbit out of an ecliptic plane has been developed. In the framework of a quasi-stationary axisymmetric self-consistent MHD model the spatial distributions of magnetic field and plasma characteristics [...] Read more.
A model capable of reproducing a set of solar wind parameters along the virtual spacecraft orbit out of an ecliptic plane has been developed. In the framework of a quasi-stationary axisymmetric self-consistent MHD model the spatial distributions of magnetic field and plasma characteristics at distances from 20 to 1200 Solar radii at almost all solar latitudes could be obtained and analyzed. This model takes into account the Sun’s magnetic field evolution during the solar cycle, when the dominant dipole magnetic field is replaced by the quadrupole one. Self-consistent solutions for solar wind characteristics were obtained, depending on the phase of the solar cycle. To verify the model, its results are compared with the observed characteristics of solar wind along the Ulysses trajectory during its flyby around the Sun from 1990 to 2009. It is shown that the results of numerical simulation are generally consistent with the observational data obtained by the Ulysses spacecraft. A comparison of the model and experimental data confirms that the model can adequately describe the solar wind parameters and can be used for heliospheric studies at different phases of the solar activity cycle, as well as in a wide range of latitudinal angles and distances to the Sun. Full article
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