scholarly journals Comparative statistical study of characteristics of plasma in planar and non-planar ICME sheaths during solar cycles 23 and 24

2020 ◽  
Vol 494 (2) ◽  
pp. 2498-2508 ◽  
Author(s):  
Zubair I Shaikh ◽  
Anil N Raghav ◽  
Geeta Vichare ◽  
Ankush Bhaskar ◽  
Wageesh Mishra
Keyword(s):  
Statistical Study ◽  
Plasma Temperature ◽  
Solar Cycles ◽  
Interplanetary Coronal Mass Ejections ◽  
Plasma Properties ◽  
Corotating Interaction Regions ◽  
Magnetic Structures ◽  
In Situ Data ◽  
Interaction Regions

ABSTRACT Planar magnetic structures (PMS) are often observed in sheath regions driven by interplanetary coronal mass ejections (ICMEs) and in corotating interaction regions (CIRs). Here, we study plasma properties statistically within planar and non-planar ICME sheath regions using in situ data from the Advanced Composition Explore (ACE) spacecraft. The study includes 420 ICME-driven sheaths from 1998–2017. We found that 146 ($\sim 35{{\ \rm per\ cent}}$) ICME-driven sheaths are planar, whereas 274 ($\sim 65{{\ \rm per\ cent}}$) are non-planar. This study found that the average plasma temperature, density, speed, plasma beta, thermal pressure and magnetic pressure are higher in planar sheaths than in non-planar sheaths. This implies that high compression plays an essential role in the formation of PMS in sheath regions. Interestingly, our analysis reveals explicitly that the strength of the southward/northward magnetic field component is almost double in planar sheath regions compared with non-planar sheath regions. This suggests that planar sheaths are more geoeffective than non-planar sheaths.

Solar Wind Interaction With Jupiter's Magnetosphere: A Statistical Study of Galileo In Situ Data and Modeled Upstream Solar Wind Conditions

2019 ◽  
Vol 124 (12) ◽  
pp. 10170-10199 ◽  
Author(s):  
Marissa F. Vogt ◽  
Szilard Gyalay ◽  
Elena A. Kronberg ◽  
Emma J. Bunce ◽  
William S. Kurth ◽  
...  
Keyword(s):  
Solar Wind ◽  
Statistical Study ◽  
Solar Wind Interaction ◽  
In Situ Data ◽  
Upstream Solar Wind

Interplanetary Shock-driven Magnetopause Compressions in Gorgon Global-MHD Simulations

2021 ◽  
Author(s):  
Ravindra Desai ◽  
Jonathan Eastwood ◽  
Joseph Eggington ◽  
Mervyn Freeman ◽  
Martin Archer ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Interplanetary Shock ◽  
Interplanetary Shocks ◽  
Pressure Balance ◽  
Interplanetary Coronal Mass Ejections ◽  
Corotating Interaction Regions ◽  
Mhd Simulations ◽  
Interaction Regions ◽  
Space Weather Event

<p>Fast-forward interplanetary interplanetary shocks, as occur at the forefront of interplanetary coronal mass ejections and at corotating interaction regions, can rapidly compress the magnetopause inside the drift paths of electrons and protons, and expose geosynchonous satellites directly to the solar wind.  Here, we use Gorgon Global-MHD simulations to study the response of the magnetopause to different fast-forward interplanetary shocks, with strengths extending from the median shocks observed during solar minimum up to that representing an extreme space weather event. The subsequent magnetopause response can be characterised by three distinct phases; an initial acceleration as inertial forces are overcome, a rapid compression well-represented by a power law, and large-scale damped oscillatory motion of the order of an Earth radius, prior to reaching pressure-balance equilibrium. The subsolar magnetopause is found to oscillate with notable frequencies in the range of 2–13 mHz over several periods of diminishing amplitudes.  These results provide an explanation for similar large-scale magnetopause oscillations observed previously during the extreme events of August 1972 and March 1991 and highlight why static magnetopause models break down during periods of strong solar wind driving.</p>

Automatic Detection and Classification of ICMEs in Solar Wind Data

2021 ◽  
Author(s):  
Hannah Ruedisser ◽  
Andreas Windisch ◽  
Ute V. Amerstorfer ◽  
Tanja Amerstorfer ◽  
Christian Moestl ◽  
...  
Keyword(s):  
Time Series ◽  
Solar Wind ◽  
Binary Classification ◽  
Warning System ◽  
Classification Problem ◽  
Learning Approaches ◽  
Process Data ◽  
Interplanetary Coronal Mass Ejections ◽  
In Situ Data ◽  
Interaction Regions

<p>Interplanetary coronal mass ejections (ICMEs) are one of the main drivers for space weather disturbances. In the past, different machine learning approaches have been used to automatically detect events in existing time series resulting from solar wind in situ data. However, classification, early detection and ultimately forecasting still remain challenges when facing the large amount of data from different instruments. We attempt to further enhance existing convolutional neural network (CNN) models through extending their possibilities to process data from multiple spacecraft and to include a post processing step commonly used in the area of computer vision. Additionally, we make an effort to extend the previously binary classification problem to a multiclass classification, to also include corotating interaction regions (CIRs) into the range of detectable phenomena. Ultimately, we aspire to explore the suitability of several other methods used in time series forecasting, in order to pave the way for the elaboration of an early warning system.</p>

Cosmic-Ray Transport in Heliospheric Magnetic Structures. II. Modeling Particle Transport through Corotating Interaction Regions

2017 ◽  
Vol 837 (1) ◽  
pp. 37 ◽  
Author(s):  
Andreas Kopp ◽  
Tobias Wiengarten ◽  
Horst Fichtner ◽  
Frederic Effenberger ◽  
Patrick Kühl ◽  
...  
Keyword(s):  
Particle Transport ◽  
Cosmic Ray ◽  
Corotating Interaction Regions ◽  
Magnetic Structures ◽  
Interaction Regions

scholarly journals Anomalous nighttime electron temperatures over Millstone Hill: a statistical study

2004 ◽  
Vol 22 (2) ◽  
pp. 431-439 ◽  
Author(s):  
V. V. Lobzin ◽  
A. V. Pavlov
Keyword(s):  
Electron Temperature ◽  
Statistical Study ◽  
Activity Index ◽  
Plasma Temperature ◽  
Occurrence Probability ◽  
Solar Cycles ◽  
Quiet Time ◽  
Maximum Probability ◽  
Geomagnetic Index ◽  
Data Set

Abstract. A statistical study of anomalous nighttime electron temperature enhancements, NETEs, observed on 336 nights during Millstone Hill radar measurements on 730 nights from 1976 to 2001 is carried out. NETEs are most frequent in winter and in autumn. The NETE occurrence has a maximum probability in February and a minimum probability in July. The asymmetry between spring and autumn NETE occurrences is found for NETEs, which are observed during geomagnetially quiet time periods. The calculated value of the NETE occurrence probability is decreased with the solar activity index F10.7 increase. The increase in a 3-h geomagnetic index Kp or the decrease in a 1-h geomagnetic index Dst leads to the increase in the NETE occurrence probability. This tendency is more pronounced for current values of Kp or Dst rather than for delayed ones and becomes more weak with the delay increase. The NETEs are most likely to begin between 19:00 and 20:00 UT. The studied NETEs are characterized by the most typical duration from 1 to 3h with the percentage peak between 1 and 2h. The electron temperature increases are predominately between 100K and 300K. We did not find any relationship between the amplitude and duration of the NETEs studied. It is shown that there is a tendency for the NETE amplitude to increase if the value of Kp or ∣Dst∣ increases. To determine whether there exists a difference between NETEs observed during different solar cycles, we chose the data subsets corresponding to 21 and 22solar cycles and performed the statistical studies for each subset. It was found that, within the errors, the corresponding dependencies are the same for the cycles considered and for the entire data set. Key words. Ionosphere (plasma temperature and density; ionospheric disturbances; modeling and forecasting)

scholarly journals Automatic Detection of Interplanetary Coronal Mass Ejections from In Situ Data: A Deep Learning Approach

2019 ◽  
Vol 874 (2) ◽  
pp. 145 ◽  
Author(s):  
Gautier Nguyen ◽  
Nicolas Aunai ◽  
Dominique Fontaine ◽  
Erwan Le Pennec ◽  
Joris Van den Bossche ◽  
...  
Keyword(s):  
Deep Learning ◽  
Coronal Mass Ejections ◽  
Automatic Detection ◽  
Learning Approach ◽  
Interplanetary Coronal Mass Ejections ◽  
In Situ Data

scholarly journals A study of solar and interplanetary parameters of CMEs causing major geomagnetic storms during SC 23

2013 ◽  
Vol 31 (8) ◽  
pp. 1285-1295 ◽  
Author(s):  
C. Oprea ◽  
M. Mierla ◽  
D. Beşliu-Ionescu ◽  
O. Stere ◽  
G. Mariş Muntean
Keyword(s):  
Energy Transfer ◽  
Geomagnetic Storms ◽  
Strong Dependence ◽  
Plasma Temperature ◽  
Proton Density ◽  
Interplanetary Coronal Mass Ejections ◽  
Superposed Epoch Analysis ◽  
Dst Index ◽  
Using Data

Abstract. In this paper we analyse 25 Earth-directed and strongly geoeffective interplanetary coronal mass ejections (ICMEs) which occurred during solar cycle 23, using data provided by instruments on SOHO (Solar and Heliospheric Observatory), ACE (Advanced Composition Explorer) and geomagnetic stations. We also examine the in situ parameters, the energy transfer into magnetosphere, and the geomagnetic indexes. We compare observed travel times with those calculated by observed speeds projected into the plane of the sky and de-projected by a simple model. The best fit was found with the projected speeds. No correlation was found between the importance of a flare and the geomagnetic Dst (disturbance storm time) index. By comparing the in situ parameters with the Dst index we find a strong connection between some of these parameters (such as Bz, Bs · V and the energy transfer into the magnetosphere) with the strength of the geomagnetic storm. No correlation was found with proton density and plasma temperature. A superposed epoch analysis revealed a strong dependence of the Dst index on the southward component of interplanetary magnetic field, Bz, and to the Akasofu coupling function, which evaluates the energy transfer between the ICME and the magnetosphere. The analysis also showed that the geomagnetic field at higher latitudes is disturbed before the field around the Earth's equator.

Four-Spacecraft Magnetic Curvature Analysis on Kelvin-Helmholtz Waves in MHD Simulations

2017 ◽  
Vol 13 (S335) ◽  
pp. 132-134
Author(s):  
R. Kieokaew ◽  
C. Foullon ◽  
B. Lavraud
Keyword(s):  
Magnetic Fields ◽  
Magnetic Energy ◽  
Regular Tetrahedron ◽  
Spatial And Temporal Scales ◽  
Magnetic Structures ◽  
Curvature Analysis ◽  
In Situ Data ◽  
Mhd Simulations ◽  
Magnetic Tension

AbstractFour-spacecraft missions are probing the Earth’s magnetospheric environment with high potential for revealing spatial and temporal scales of a variety of in-situ phenomena. Magnetic curvature is intrinsic to curved magnetic fields where the magnetic energy is stored in the form of magnetic tension. In-situ magnetic curvature has been resolved by the four-spacecraft technique called “magnetic curvature analysis” (MCA). We test the MCA on 2.5D MHD simulations of curved magnetic structures induced by Kelvin-Helmholtz (KH) waves, with increasing (regular) tetrahedron sizes of virtual spacecraft. We have found variations of the curvature vectors both in radii and orientations depending on the sizes of the tetrahedron. This is helpful to better understand the MCA measures when the technique is applied to in-situ data without knowing the scale sizes of plasma structures under consideration. This study lends support for cross-scale observations to better understand the nature of curvature and its role in plasma phenomena.

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