A critical look at studying the interplanetary drivers of the magnetospheric disturbances

Author(s):  
Yuri Yermolaev ◽  
Irina Lodkina ◽  
Lidia Dremukhina ◽  
Michael Yermolaev ◽  
Alexander Khokhlachev

<p>Although the main types of solar wind (the so-called interplanetary drivers), which may contain the southward component of the interplanetary magnetic field (Bz <0) and cause disturbances in the magnetosphere, have long been known, it has only recently been discovered that different types of drivers cause a different reaction of the magnetosphere for identical field variations (Borovsky and Denton,2006, Yermolaev et al., 2013). This discovery led to a significant increase in the number of investigations studying the response of the magnetosphere-ionosphere system to various drivers. At the same time, the number of incorrect approaches in this direction of research has increased. These errors can be attributed to 4 large classes. (1) First class includes works whose authors uncritically reacted to previously published works and use incorrect results to identify types of drivers. (2) Some authors independently incorrectly identified driver types. (3) Very often, authors associate the perturbation of the magnetosphere-ionosphere system caused by a complex driver (a sequence of single drivers) with one of the drivers, ignoring the complex nature. For example, a magnetic storm is often caused by a compression region Sheath in front of an interplanetary CME (ICME), but the authors consider the ICME to be a cause of disturbance, not Sheath. (4) Finally, there is a “lost driver” of magnetospheric disturbances: some authors simply do not consider the Sheath compression region before ICME if there is no interplanetary shock (IS) before Sheath, although this type of driver, “Sheath without IS”, generates about 10% of moderate and strong geomagnetic storms (Yermolaev et al., 2017, 2020). These errors lead to numerous mistakes and incorrect conclusions.<br>The work is supported by the RFFI grant 19-02-00177а. </p><p>References<br>Borovsky, J. E., and M. H. Denton (2006), Differences between CME‐driven storms and CIR‐driven storms, J. Geophys. Res., 111, A07S08, doi:10.1029/2005JA011447</p><p>Yermolaev, Y. I., N. S. Nikolaeva, I. G. Lodkina, and M. Y. Yermolaev (2012), Geoeffectiveness and efficiency of CIR, sheath, and ICME in generation of magnetic storms, J. Geophys. Res., 117, A00L07, doi:10.1029/2011JA017139</p><p><br>Yermolaev, Y.I., Lodkina, I.G., Nikolaeva, N.S. et al. (2017), Some problems of identifying types of large-scale solar wind and their role in the physics of the magnetosphere, Cosmic Res. 55: 178. https://doi.org/10.1134/S0010952517030029</p><p>Yermolaev, Y.I., Lodkina, I.G., et al. (2020), Some problems of identifying types of large-scale solar wind and their role in the physics of the magnetosphere. 4. Lost driver, Cosmic Res. 59, in press</p><p> </p>

2012 ◽  
Vol 2 (10) ◽  
pp. 1-3 ◽  
Author(s):  
Praveen Kumar Gupta ◽  
◽  
Puspraj Singh Puspraj Singh ◽  
Puspraj Singh Puspraj Singh ◽  
P. K. Chamadia P. K. Chamadia

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 138
Author(s):  
Yuri I. Yermolaev ◽  
Irina G. Lodkina ◽  
Lidia A. Dremukhina ◽  
Michael Y. Yermolaev ◽  
Alexander A. Khokhlachev

One of the most promising methods of research in solar–terrestrial physics is the comparison of the responses of the magnetosphere–ionosphere–atmosphere system to various types of interplanetary disturbances (so-called “interplanetary drivers”). Numerous studies have shown that different types of drivers result in different reactions of the system for identical variations in the interplanetary magnetic field. In particular, the sheaths—compression regions before fast interplanetary CMEs (ICMEs)—have higher efficiency in terms of the generation of magnetic storms than ICMEs. The growing popularity of this method of research is accompanied by the growth of incorrect methodological approaches in such studies. These errors can be divided into four main classes: (i) using incorrect data with the identification of driver types published in other studies; (ii) using incorrect methods to identify the types of drivers and, as a result, misclassify the causes of magnetospheric-ionospheric disturbances; (iii) ignoring a frequent case with a complex, composite, nature of the driver (the presence of a sequence of several simple drivers) and matching the system response with only one of the drivers; for example, a magnetic storm is often generated by a sheath in front of ICME, although the authors consider these events to be a so-called “CME-induced” storm, rather than a “sheath-induced” storm; (iv) ignoring the compression regions before the fast CME in the case when there is no interplanetary shock (IS) in front of the compression region (“sheath without IS” or the so-called “lost driver”), although this type of driver generates about 10% of moderate and large magnetic storms. Possible ways of solving this problem are discussed.


2005 ◽  
Vol 23 (2) ◽  
pp. 609-624 ◽  
Author(s):  
K. E. J. Huttunen ◽  
J. Slavin ◽  
M. Collier ◽  
H. E. J. Koskinen ◽  
A. Szabo ◽  
...  

Abstract. Sudden impulses (SI) in the tail lobe magnetic field associated with solar wind pressure enhancements are investigated using measurements from Cluster. The magnetic field components during the SIs change in a manner consistent with the assumption that an antisunward moving lateral pressure enhancement compresses the magnetotail axisymmetrically. We found that the maximum variance SI unit vectors were nearly aligned with the associated interplanetary shock normals. For two of the tail lobe SI events during which Cluster was located close to the tail boundary, Cluster observed the inward moving magnetopause. During both events, the spacecraft location changed from the lobe to the magnetospheric boundary layer. During the event on 6 November 2001 the magnetopause was compressed past Cluster. We applied the 2-D Cartesian model developed by collier98 in which a vacuum uniform tail lobe magnetic field is compressed by a step-like pressure increase. The model underestimates the compression of the magnetic field, but it fits the magnetic field maximum variance component well. For events for which we could determine the shock normal orientation, the differences between the observed and calculated shock propagation times from the location of WIND/Geotail to the location of Cluster were small. The propagation speeds of the SIs between the Cluster spacecraft were comparable to the solar wind speed. Our results suggest that the observed tail lobe SIs are due to lateral increases in solar wind dynamic pressure outside the magnetotail boundary.


2020 ◽  
Author(s):  
Yuri Yermolaev ◽  
Irina Lodkina ◽  
Alexander Khokhlachev ◽  
Michael Yermolaev ◽  
Natalia Borodkova ◽  
...  

2021 ◽  
Author(s):  
Sujan Prasad Gautam ◽  
Ashok Silwal ◽  
Prakash Poudel ◽  
Monika Karki ◽  
Binod Adhikari ◽  
...  

2021 ◽  
Author(s):  
Harlan Spence ◽  
Kristopher Klein ◽  
HelioSwarm Science Team

<p>Recently selected for phase A study for NASA’s Heliophysics MidEx Announcement of Opportunity, the HelioSwarm Observatory proposes to transform our understanding of the physics of turbulence in space and astrophysical plasmas by deploying nine spacecraft to measure the local plasma and magnetic field conditions at many points, with separations between the spacecraft spanning MHD and ion scales.  HelioSwarm resolves the transfer and dissipation of turbulent energy in weakly-collisional magnetized plasmas with a novel configuration of spacecraft in the solar wind. These simultaneous multi-point, multi-scale measurements of space plasmas allow us to reach closure on two science goals comprised of six science objectives: (1) reveal how turbulent energy is transferred in the most probable, undisturbed solar wind plasma and distributed as a function of scale and time; (2) reveal how this turbulent cascade of energy varies with the background magnetic field and plasma parameters in more extreme solar wind environments; (3) quantify the transfer of turbulent energy between fields, flows, and ion heat; (4) identify thermodynamic impacts of intermittent structures on ion distributions; (5) determine how solar wind turbulence affects and is affected by large-scale solar wind structures; and (6) determine how strongly driven turbulence differs from that in the undisturbed solar wind. </p>


2021 ◽  
Author(s):  
Merav Opher ◽  
James Drake ◽  
Gary Zank ◽  
Gabor Toth ◽  
Erick Powell ◽  
...  

Abstract The heliosphere is the bubble formed by the solar wind as it interacts with the interstellar medium (ISM). Studies show that the solar magnetic field funnels the heliosheath solar wind (the shocked solar wind at the edge of the heliosphere) into two jet-like structures1-2. Magnetohydrodynamic simulations show that these heliospheric jets become unstable as they move down the heliotail1,3 and drive large-scale turbulence. However, the mechanism that produces of this turbulence had not been identified. Here we show that the driver of the turbulence is the Rayleigh-Taylor (RT) instability caused by the interaction of neutral H atoms streaming from the ISM with the ionized matter in the heliosheath (HS). The drag between the neutral and ionized matter acts as an effective gravity which causes a RT instability to develop along the axis of the HS magnetic field. A density gradient exists perpendicular to this axis due to the confinement of the solar wind by the solar magnetic field. The characteristic time scale of the instability depends on the neutral H density in the ISM and for typical values the growth rate is ~ 3 years. The instability destroys the coherence of the heliospheric jets and magnetic reconnection ensues, allowing ISM material to penetrate the heliospheric tail. Signatures of this instability should be observable in Energetic Neutral Atom (ENA) maps from future missions such as IMAP4. The turbulence driven by the instability is macroscopic and potentially has important implications for particle acceleration.


2021 ◽  
Author(s):  
Jana Šafránková ◽  
Zdeněk Němeček ◽  
František Němec ◽  
Luca Franci ◽  
Alexander Pitňa

<p>The solar wind is a unique laboratory to study the turbulent processes occurring in a collisionless plasma with high Reynolds numbers. A turbulent cascade—the process that transfers the free energy contained within the large scale fluctuations into the smaller ones—is believed to be one of the most important mechanisms responsible for heating of the solar corona and solar wind. The paper analyzes power spectra of solar wind velocity, density and magnetic field fluctuations that are computed in the frequency range around the break between inertial and kinetic scales. The study uses measurements of the Bright Monitor of the Solar Wind (BMSW) on board the Spektr-R spacecraft with a time resolution of 32 ms complemented with 10 Hz magnetic field observations from the Wind spacecraft propagated to the Spektr-R location. The statistics based on more than 42,000 individual spectra show that: (1) the spectra of both quantities can be fitted by two (three in the case of the density) power-law segments; (2) the median slopes of parallel and perpendicular fluctuation velocity and magnetic field components are different; (3) the break between MHD and kinetic scales as well as the slopes are mainly controlled by the ion beta parameter. These experimental results are compared with high-resolution 2D hybrid particle-in-cell simulations, where the electrons are considered to be a massless, charge-neutralizing fluid with a constant temperature, whereas the ions are described as macroparticles representing portions of their distribution function. In spite of several limitations (lack of the electron kinetics, lower dimensionality), the model results agree well with the experimental findings. Finally, we discuss differences between observations and simulations in relation to the role of important physical parameters in determining the properties of the turbulent cascade.</p>


2010 ◽  
Vol 28 (2) ◽  
pp. 515-530 ◽  
Author(s):  
H. Korth ◽  
B. J. Anderson ◽  
C. L. Waters

Abstract. The spatial distributions of large-scale field-aligned Birkeland currents have been derived using magnetic field data obtained from the Iridium constellation of satellites from February 1999 to December 2007. From this database, we selected intervals that had at least 45% overlap in the large-scale currents between successive hours. The consistency in the current distributions is taken to indicate stability of the large-scale magnetosphere–ionosphere system to within the spatial and temporal resolution of the Iridium observations. The resulting data set of about 1500 two-hour intervals (4% of the data) was sorted first by the interplanetary magnetic field (IMF) GSM clock angle (arctan(By/Bz)) since this governs the spatial morphology of the currents. The Birkeland current densities were then corrected for variations in EUV-produced ionospheric conductance by normalizing the current densities to those occurring for 0° dipole tilt. To determine the dependence of the currents on other solar wind variables for a given IMF clock angle, the data were then sorted sequentially by the following parameters: the solar wind electric field in the plane normal to the Earth–Sun line, Eyz; the solar wind ram pressure; and the solar wind Alfvén Mach number. The solar wind electric field is the dominant factor determining the Birkeland current intensities. The currents shift toward noon and expand equatorward with increasing solar wind electric field. The total current increases by 0.8 MA per mV m−1 increase in Eyz for southward IMF, while for northward IMF it is nearly independent of the electric field, increasing by only 0.1 MA per mV m−1 increase in Eyz. The dependence on solar wind pressure is comparatively modest. After correcting for the solar dynamo dependencies in intensity and distribution, the total current intensity increases with solar wind dynamic pressure by 0.4 MA/nPa for southward IMF. Normalizing the Birkeland current densities to both the median solar wind electric field and dynamic pressure effects, we find no significant dependence of the Birkeland currents on solar wind Alfvén Mach number.


2011 ◽  
Vol 29 (10) ◽  
pp. 1809-1826 ◽  
Author(s):  
H. Korth ◽  
L. Rastätter ◽  
B. J. Anderson ◽  
A. J. Ridley

Abstract. Spatial distributions of the large-scale Birkeland currents derived from magnetic field data acquired by the constellation of Iridium Communications satellites have been compared with global-magnetosphere magneto-hydrodynamic (MHD) simulations. The Iridium data, spanning the interval from February 1999 to December 2007, were first sorted into 45°-wide bins of the interplanetary magnetic field (IMF) clock angle, and the dependencies of the Birkeland currents on solar wind electric field magnitude, Eyz, ram pressure, psw, and Alfvén Mach number, MA, were then examined within each bin. The simulations have been conducted at the publicly-accessible Community Coordinated Modeling Center using the University of Michigan Space Weather modeling Framework, which features a global magnetosphere model coupled to the Rice Convection Model. In excess of 120 simulations with steady-state conditions were executed to yield the dependencies of the Birkeland currents on the solar wind and IMF parameters of the coupled model. Averaged over all IMF orientations, the simulation reproduces the Iridium statistical Birkeland current distributions with a two-dimensional correlation coefficient of about 0.8, and the total current agrees with the climatology averages to within 10%. The total current for individual events regularly exceeds those computed from statistical distributions by factors of ≥2, resulting in larger disparities between observations and simulations. The simulation results also qualitatively reflect the observed increases in total current with increasing Eyz and psw, but the model underestimates the rate of increase by up to 50%. The equatorward expansion and shift of the large-scale currents toward noon observed for increasing Eyz are also evident in the simulation current patterns. Consistent with the observations, the simulation does not show a significant dependence of the total current on MA.


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