Global magnetic structure of the quasi-steady solar wind

1996 ◽  
Author(s):  
V. J. Pizzo
Keyword(s):  
Solar Wind ◽  
Magnetic Structure

scholarly journals Solar-Wind Structures That Are Not Destroyed by the Action of Solar-Wind Turbulence

2021 ◽  
Vol 8 ◽  
Author(s):  
Joseph E. Borovsky
Keyword(s):  
Solar Wind ◽  
Magnetic Structure ◽  
Solar Wind Plasma ◽  
Ion Composition ◽  
Mhd Turbulence ◽  
Current Sheets ◽  
Wind Structure ◽  
Solar Wind Structure ◽  
Wind Measurements ◽  
Dominant Process

If MHD turbulence is a dominant process acting in the solar wind between the Sun and 1 AU, then the destruction and regeneration of structure in the solar-wind plasma is expected. Six types of solar-wind structure at 1 AU that are not destroyed by turbulence are examined: 1) corotating-interaction-region stream interfaces, 2) periodic density structures, 3) magnetic structure anisotropy, 4) ion-composition boundaries and their co-located current sheets, 5) strahl-intensity boundaries and their co-located current sheets, and 6) non-evolving Alfvénic magnetic structure. Implications for the solar wind and for turbulence in the solar wind are highlighted and a call for critical future solar-wind measurements is given.

scholarly journals MagneToRE: Mapping the 3-D Magnetic Structure of the Solar Wind Using a Large Constellation of Nanosatellites

2021 ◽  
Vol 8 ◽  
Author(s):  
Bennett A. Maruca ◽  
Jeffersson A. Agudelo Rueda ◽  
Riddhi Bandyopadhyay ◽  
Federica B. Bianco ◽  
Alexandros Chasapis ◽  
...  
Keyword(s):  
Machine Learning ◽  
Solar Wind ◽  
Form Factor ◽  
Magnetic Structure ◽  
Data Science ◽  
Fluxgate Magnetometer ◽  
Scientific Instruments ◽  
Astrophysical Plasmas ◽  
First Time

Unlike the vast majority of astrophysical plasmas, the solar wind is accessible to spacecraft, which for decades have carried in-situ instruments for directly measuring its particles and fields. Though such measurements provide precise and detailed information, a single spacecraft on its own cannot disentangle spatial and temporal fluctuations. Even a modest constellation of in-situ spacecraft, though capable of characterizing fluctuations at one or more scales, cannot fully determine the plasma’s 3-D structure. We describe here a concept for a new mission, the Magnetic Topology Reconstruction Explorer (MagneToRE), that would comprise a large constellation of in-situ spacecraft and would, for the first time, enable 3-D maps to be reconstructed of the solar wind’s dynamic magnetic structure. Each of these nanosatellites would be based on the CubeSat form-factor and carry a compact fluxgate magnetometer. A larger spacecraft would deploy these smaller ones and also serve as their telemetry link to the ground and as a host for ancillary scientific instruments. Such an ambitious mission would be feasible under typical funding constraints thanks to advances in the miniaturization of spacecraft and instruments and breakthroughs in data science and machine learning.

scholarly journals Understanding the variability of magnetic storms caused by ICMEs

2017 ◽  
Vol 35 (1) ◽  
pp. 147-159 ◽  
Author(s):  
Remi Benacquista ◽  
Sandrine Rochel ◽  
Guy Rolland
Keyword(s):  
Solar Wind ◽  
Magnetic Structure ◽  
Large Scale ◽  
Temporal Dynamics ◽  
Magnetic Storms ◽  
Magnetic Clouds ◽  
Interplanetary Coronal Mass Ejections ◽  
Superposed Epoch Analysis ◽  
Original Insight ◽  
Ambient Solar Wind

Abstract. In this paper, we study the dynamics of magnetic storms due to interplanetary coronal mass ejections (ICMEs). We used multi-epoch superposed epoch analyses (SEAs) with a choice of epoch times based on the structure of the events. By sorting the events with respect to simple large-scale features (presence of a shock, magnetic structure, polarity of magnetic clouds), this method provides an original insight into understanding the variability of magnetic storm dynamics. Our results show the necessity of seeing ICMEs and their preceding sheaths as a whole since each substructure impacts the other and has an effect on its geoeffectiveness. It is shown that the presence of a shock drives the geoeffectiveness of the sheaths, while both the shock and the magnetic structure impact the geoeffectiveness of the ICMEs. In addition, we showed that the ambient solar wind characteristics are not the same for ejecta and magnetic clouds (MCs). The ambient solar wind upstream magnetic clouds are quieter than upstream ejecta and particularly slower. We also focused on the polarity of magnetic clouds since it drives not only their geoeffectiveness but also their temporal dynamics. South–north magnetic clouds (SN-MCs) and north–south magnetic clouds (NS-MCs) show no difference in geoeffectiveness for our sample of events. Lastly, since it is well-known that sequences of events can possibly induce strong magnetic storms, such sequences have been studied using superposed epoch analysis (SEA) for the first time. We found that these sequences of ICMEs are very usual and concern about 40 % of the ICMEs. Furthermore, they cause much more intense magnetic storms than isolated events do.

Relating CME density derived from remote sensing data to CME sheath solar wind plasma pile up as measured in-situ

2020 ◽  
Author(s):  
Manuela Temmer ◽  
Lukas Holzknecht ◽  
Mateja Dumbovic ◽  
Bojan Vrsnak ◽  
Nishtha Sachdeva ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Structure ◽  
Interplanetary Space ◽  
Remote Sensing Data ◽  
Solar Wind Plasma ◽  
Proton Density ◽  
Observational Assessment ◽  
Sheath Region ◽  
Pile Up

<p>For better estimating the drag force acting on coronal mass ejections (CMEs) in interplanetary space and ram-pressure at planets, improved knowledge of the evolution of CME density/mass is highly valuable. We investigate a sample of 29 well observed CME-ICME events, for which we determine the de-projected 3D mass (STEREO-A and -B data), and the CME volume using GCS modeling (STEREO, SoHO). Expanding the volume to 1AU distance, we derive the density and compare the results to in-situ proton density measurements separately for the ICME sheath and magnetic structure. A fair agreement between calculated and measured density is derived for the magnetic structure as well for the sheath if taking into account mass pile up of solar wind plasma. We give evidence and observational assessment that during the interplanetary propagation of a CME 1) the magnetic structure has rather constant mass and 2) the sheath region at the front of the driver is formed from piled-up mass that is rather depending on the solar wind density ahead of the CME, than on the CME speed. </p>

Evolution of planar magnetic structure within the stream interaction region and its connection with a recurrent Forbush decrease

2020 ◽  
Vol 494 (4) ◽  
pp. 5075-5080 ◽  
Author(s):  
Zubair I Shaikh ◽  
Anil N Raghav ◽  
Geeta Vichare
Keyword(s):  
Solar Wind ◽  
Magnetic Structure ◽  
Forbush Decrease ◽  
Cosmic Ray ◽  
Mass Function ◽  
Recovery Phase ◽  
Initial Mass Function ◽  
Interaction Region ◽  
Slow Solar Wind ◽  
Cosmic Ray Intensity

ABSTRACT In general, stream interaction region (SIR)-induced Forbush decreases are recurrent and low magnitude in nature. The diffusion–convection associated with the SIR plays an important role in their modulation. Here, we study the evolution of planar magnetic structure (PMS) within the SIR and its contribution to cosmic ray modulation. Interestingly, we found the presence of PMS structures within the SIR from the leading part of the SIR to the minimum of the cosmic ray intensity in two events. The PMS may have originated due to the high compression caused by the fast solar wind, which amplifies and aligns the pre-existing discontinuities in the ambient slow solar wind. The study also suggests that the existence of PMS, enhanced initial mass function (IMF) strength, and associated turbulent regions decreases the perpendicular diffusion coefficient and causes a decrease in the cosmic ray intensity observed on Earth. Moreover, a slow decrease in IMF magnitude concurs with the recovery phase of cosmic ray intensity.

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