scholarly journals Role of Magnetospheric Plasma Physics for Understanding Cosmic Phenomena

1990 ◽  
Vol 115 ◽  
pp. 90-93 ◽  
Author(s):  
Indra Mohan Lal Das
Keyword(s):  
Solar Wind ◽  
Plasma Physics ◽  
Laboratory Experiments ◽  
Magnetospheric Plasma ◽  
Proper Understanding ◽  
In Situ Observations

AbstractCosmic phenomena occur in the remote regions of space where in-situ observations are not possible. For proper understanding of these phenomena laboratory experiments are essential, but the in-situ observations of magnetospheric plasma provides even a better background to test various hypothesis of cosmic interest. This is because the ionospheric-magnetospheric plasma and the solar wind are the only cosmic plasmas accessible to extensive in-situ observations and experiments.

Solar wind radial evolution via future multi-spacecraft in-situ observations

2020 ◽  
Author(s):  
Štěpán Štverák ◽  
Milan Maksimovic ◽  
Petr Hellinger ◽  
Pavel M. Trávníček
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Single Point ◽  
Solar Wind Plasma ◽  
Future Events ◽  
In Situ Observations ◽  
Radial Evolution ◽  
The Individual

<p>Our understanding of the solar wind evolution, its energy budget, and role of the key mechanisms providing the energy exchange between the plasma particles and electromagnetic fluctuations along the expansion, is highly limited by the single point nature of most in situ spacecraft measurements. Obviously it is difficult to observe and track the individual processes in space and time from this narrow perspective. One way to improve our knowledge of these large-scale variations is to employ multi-spacecraft observations, namely rather rare so called line-up events where one can potentially observe the true evolution of individual solar wind plasma parcels. A pioneering work in this field was done using Helios I&II missions. Here we present an analyses of using such tool for future events predicted to be available from the very recent missions Parker Solar Probe and Solar Orbiter (and optionally BepiColombo).</p>

scholarly journals MESSENGER observations of planetary ion enhancements at Mercury’s northern magnetospheric cusp during Flux Transfer Event Showers

2021 ◽  
Author(s):  
Weijie Sun ◽  
James Slavin ◽  
Anna Milillo ◽  
Ryan Dewey ◽  
Stefano Orsini ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Transfer Event ◽  
Order Of Magnitude ◽  
In Situ Observations ◽  
Flux Transfer ◽  
Magnetospheric Cusp ◽  
Upward Moving ◽  
Entry Layer

Abstract At Mercury, several processes can release ions and neutrals out of the planet’s surface. Here we present enhancements of dayside planetary ions in the solar wind entry layer during flux transfer event (FTE) “showers” near Mercury’s northern magnetospheric cusp. In this entry layer, solar wind ions are accelerated and move downward (i.e. planetward) toward the cusps, which sputter upward-moving planetary ions within 1 minute. The precipitation rate is enhanced by an order of magnitude during FTE showers and the neutral density of the exosphere can vary by >10% due to this FTE-driven sputtering. These in situ observations of enhanced planetary ions in the entry layer likely correspond to an escape channel of Mercury’s planetary ions, and the large-scale variations of the exosphere observed on minute-timescales by ground-based telescopes. Comprehensive, future multi-point measurements made by BepiColombo will greatly enhance our understanding of the processes contributing to Mercury’s dynamic exosphere and magnetosphere.

scholarly journals Evidence for Particle Acceleration During Magnetospheric Substorms

1994 ◽  
Vol 142 ◽  
pp. 531-539
Author(s):  
Ramon E. Lopez ◽  
Daniel N. Baker
Keyword(s):  
Solar Wind ◽  
Particle Acceleration ◽  
Energy Release ◽  
Acceleration Of Particles ◽  
Magnetospheric Substorms ◽  
Geomagnetic Tail ◽  
Dissipation Of Energy ◽  
In Situ Observations ◽  
Current Systems

AbstractMagnetospheric substorms represent the episodic dissipation of energy stored in the geomagnetic tail that was previously extracted from the solar wind. This energy release produces activity throughout the entire magnetosphere-ionosphere system, and it results in a wide variety of phenomena such as auroral intensifications and the generation of new current systems. All of these phenomena involve the acceleration of particles, sometimes up to several MeV. In this paper we present a brief overview of substorm phenomenology. We then review some of the evidence for particle acceleration in Earth’s magnetosphere during substorms. Such in situ observations in this most accessible of all cosmic plasma domains may hold important clues to understanding acceleration processes in more distant astrophysical systems.Subject headings: acceleration of particles — Earth — solar wind

scholarly journals The role of DYNAMO in situ observations in improving NASA CERES-like daily surface and atmospheric radiative flux estimates

2017 ◽  
Vol 4 (4) ◽  
pp. 164-183 ◽  
Author(s):  
Hailan Wang ◽  
Wenying Su ◽  
Norman G. Loeb ◽  
Deepthi Achuthavarier ◽  
Siegfried D. Schubert
Keyword(s):  
Radiative Flux ◽  
In Situ Observations

scholarly journals MHD Modeling of the Background Solar Wind in the Inner Heliosphere From 0.1 to 5.5 AU: Comparison With In Situ Observations

Space Weather ◽  
2020 ◽  
Vol 18 (6) ◽  
Author(s):  
Y. X. Wang ◽  
X. C. Guo ◽  
C. Wang ◽  
V. Florinski ◽  
F. Shen ◽  
...  
Keyword(s):  
Solar Wind ◽  
Mhd Modeling ◽  
In Situ Observations ◽  
Inner Heliosphere

scholarly journals Understanding the origins of the heliosphere: integrating observations and measurements from Parker Solar Probe, Solar Orbiter, and other space- and ground-based observatories

2020 ◽  
Vol 642 ◽  
pp. A4 ◽  
Author(s):  
M. Velli ◽  
L. K. Harra ◽  
A. Vourlidas ◽  
N. Schwadron ◽  
O. Panasenco ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Fields ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Coronal Plasma ◽  
Solar Dynamics Observatory ◽  
Surface Magnetic Field ◽  
In Situ Observations

Context. The launch of Parker Solar Probe (PSP) in 2018, followed by Solar Orbiter (SO) in February 2020, has opened a new window in the exploration of solar magnetic activity and the origin of the heliosphere. These missions, together with other space observatories dedicated to solar observations, such as the Solar Dynamics Observatory, Hinode, IRIS, STEREO, and SOHO, with complementary in situ observations from WIND and ACE, and ground based multi-wavelength observations including the DKIST observatory that has just seen first light, promise to revolutionize our understanding of the solar atmosphere and of solar activity, from the generation and emergence of the Sun’s magnetic field to the creation of the solar wind and the acceleration of solar energetic particles. Aims. Here we describe the scientific objectives of the PSP and SO missions, and highlight the potential for discovery arising from synergistic observations. Here we put particular emphasis on how the combined remote sensing and in situ observations of SO, that bracket the outer coronal and inner heliospheric observations by PSP, may provide a reconstruction of the solar wind and magnetic field expansion from the Sun out to beyond the orbit of Mercury in the first phases of the mission. In the later, out-of-ecliptic portions of the SO mission, the solar surface magnetic field measurements from SO and the multi-point white-light observations from both PSP and SO will shed light on the dynamic, intermittent solar wind escaping from helmet streamers, pseudo-streamers, and the confined coronal plasma, and on solar energetic particle transport. Methods. Joint measurements during PSP–SO alignments, and magnetic connections along the same flux tube complemented by alignments with Earth, dual PSP–Earth, and SO-Earth, as well as with STEREO-A, SOHO, and BepiColumbo will allow a better understanding of the in situ evolution of solar-wind plasma flows and the full three-dimensional distribution of the solar wind from a purely observational point of view. Spectroscopic observations of the corona, and optical and radio observations, combined with direct in situ observations of the accelerating solar wind will provide a new foundation for understanding the fundamental physical processes leading to the energy transformations from solar photospheric flows and magnetic fields into the hot coronal plasma and magnetic fields and finally into the bulk kinetic energy of the solar wind and solar energetic particles. Results. We discuss the initial PSP observations, which already provide a compelling rationale for new measurement campaigns by SO, along with ground- and space-based assets within the synergistic context described above.

Solar Orbiter observations of magnetic Kelvin-Helmholtz waves in the solar wind

2021 ◽  
Author(s):  
Rungployphan Kieokaew ◽  
Benoit Lavraud ◽  
David Ruffolo ◽  
William Matthaeus ◽  
Yan Yang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Heliospheric Current Sheet ◽  
Shear Instability ◽  
Slow Solar Wind ◽  
Flow Shear ◽  
In Situ Observations ◽  
Set Up ◽  
Nonlinear Shear ◽  
Wind Source

<p>The Kelvin-Helmholtz instability (KHI) is a nonlinear shear-driven instability that develops at the interfaces between shear flows in plasmas. KHI is ubiquitous in plasmas and has been observed in situ at planetary interfaces and at the boundaries of coronal mass ejections in remote-sensing observations. KHI is also expected to develop at flow shear interfaces in the solar wind, but while it was hypothesized to play an important role in the mixing of plasmas and exciting solar wind fluctuations, its direct observation in the solar wind was still lacking. We report first in-situ observations of ongoing KHI in the solar wind using Solar Orbiter during its cruise phase. The KHI is found in a shear layer in the slow solar wind near the Heliospheric Current Sheet. We find that the observed conditions satisfy the KHI onset criterion from linear theory and the steepening of the shear boundary layer is consistent with the development of KH vortices. We further investigate the solar wind source of this event to understand the conditions that support KH growth. In addition, we set up a local MHD simulation using the empirical values to reproduce the observed KHI. This observed KHI in the solar wind provides robust evidence that shear instability develops in the solar wind, with obvious implications in the driving of solar wind fluctuations and turbulence. The reasons for the lack of previous such measurements are also discussed.</p>

Understanding Solar Wind Formation by Identifying the Origins of In Situ Observations 

2021 ◽  
Author(s):  
Samantha Wallace ◽  
Nicholeen M. Viall ◽  
Charles N. Arge
Keyword(s):  
Solar Wind ◽  
Solar Wind Speed ◽  
Source Region ◽  
Heliospheric Current Sheet ◽  
Slow Solar Wind ◽  
The Sun ◽  
Flux Transport ◽  
Model Driven ◽  
In Situ Observations

<p>Solar wind formation can be separated into three physical steps – source, release, and acceleration – that each leave distinct observational signatures on plasma parcels.  The Wang-Sheeley-Arge (WSA) model driven by Air Force Data Assimilative Photospheric Flux Transport (ADAPT) time-dependent photospheric field maps now has the ability to connect in situ observations more rigorously to their precise source at the Sun, allowing us to investigate the physical processes involved in solar wind formation.   In this talk, I will highlight my PhD dissertation research in which we use the ADAPT-WSA model to either characterize the solar wind emerging from specific sources, or investigate the formation process of various solar wind populations.  In the first study, we test the well-known inverse relationship between expansion factor (f<sub>s</sub>) and observed solar wind speed (v<sub>obs</sub>) for solar wind that emerges from a large sampling of pseudostreamers, to investigate if field line expansion plays a physical role in accelerating the solar wind from this source region.  We find that there is no correlation between f<sub>s</sub> and v<sub>obs</sub> at pseudostreamer cusps. In the second study, we determine the source locations of the first identified quasiperiodic density structures (PDSs) inside 0.6 au. Our modeling provides confirmation of these events forming via magnetic reconnection both near to and far from the heliospheric current sheet (HCS) – a direct test of the Separatrix-web (S-web) theory of slow solar wind formation.  In the final study, we use our methodology to identify the source regions of the first observations from the Parker Solar Probe (PSP) mission.  Our modeling enabled us to characterize the closest to the Sun observed coronal mass ejection (CME) to date as a streamer blowout.  We close with future ways that ADAPT-WSA can be used to test outstanding questions of solar wind formation.</p>

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