scholarly journals Theoretical Interpretation of Traveling Interplanetary Phenomena and Their Solar Origins

1980 ◽  
Vol 91 ◽  
pp. 443-458 ◽  
Author(s):  
S. T. Wu
Keyword(s):  
Solar Wind ◽  
Wave Propagation ◽  
Interplanetary Shock ◽  
Theoretical Interpretation ◽  
Theoretical Studies ◽  
Interplanetary Shocks ◽  
Physical Processes ◽  
Mathematical Methods ◽  
Microscopic Approach ◽  
Alternative Approaches

Recent theoretical studies on Traveling Interplanetary Phenomena (TIP) and their relation or presumed relation to their solar origins will be reviewed. An attempt is made to outline the theoretical studies in the context of mathematical methods and physical processes. The following alternative approaches are examined: analytical vs. numerical methods; magnetohydrodynamics vs. hydrodynamics; processes with or without dissipation; continuum (macroscopic) vs. the kinetic (microscopic) approach. In particular, the flare-generated interplanetary shocks are used as examples to illustrate these theoretical studies within the context of TIP. Some emphasis will be placed on MHD wave propagation through the inner corona and its maturity to a fully-developed interplanetary shock. Further, their propagation and the disturbing effects on the solar wind will be considered. Cases concerning the classification and characteristics of blast-produced shocks and long-lasting ejecta are also discussed in the context of numerical simulations.

scholarly journals Cluster observations of sudden impulses in the magnetotail caused by interplanetary shocks and pressure increases

2005 ◽  
Vol 23 (2) ◽  
pp. 609-624 ◽  
Author(s):  
K. E. J. Huttunen ◽  
J. Slavin ◽  
M. Collier ◽  
H. E. J. Koskinen ◽  
A. Szabo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Speed ◽  
Interplanetary Shock ◽  
Wind Pressure ◽  
Shock Propagation ◽  
Interplanetary Shocks ◽  
Maximum Variance ◽  
The Magnetic Field

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.

scholarly journals Formation of a strong southward IMF near the solar maximum of cycle 23

2004 ◽  
Vol 22 (2) ◽  
pp. 673-687 ◽  
Author(s):  
S. Watari ◽  
M. Vandas ◽  
T. Watanabe
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Geomagnetic Storms ◽  
Solar Maximum ◽  
Interplanetary Shocks ◽  
Physical Processes ◽  
Interplanetary Magnetic Fields ◽  
Interplanetary Physics ◽  
Solar Wind Parameters ◽  
Interplanetary Disturbance

Abstract. We analyzed observations of the solar activities and the solar wind parameters associated with large geomagnetic storms near the maximum of solar cycle 23. This analysis showed that strong southward interplanetary magnetic fields (IMFs), formed through interaction between an interplanetary disturbance, and background solar wind or between interplanetary disturbances are an important factor in the occurrence of intense geomagnetic storms. Based on our analysis, we seek to improve our understanding of the physical processes in which large negative Bz's are created which will lead to improving predictions of space weather. Key words. Interplanetary physics (Flare and stream dynamics; Interplanetary magnetic fields; Interplanetary shocks)

scholarly journals In situ local shock speed and transit shock speed

1998 ◽  
Vol 16 (4) ◽  
pp. 370-375 ◽  
Author(s):  
S. Watari ◽  
T. Detman
Keyword(s):  
Solar Wind ◽  
Solar Wind Plasma ◽  
Interplanetary Shock ◽  
Propagation Model ◽  
Interplanetary Shocks ◽  
Shock Speed ◽  
Interplanetary Physics ◽  
Speed Solar Wind ◽  
Transit Speed

Abstract. A useful index for estimating the transit speeds was derived by analyzing interplanetary shock observations. This index is the ratio of the in situ local shock speed and the transit speed; it is 0.6–0.9 for most observed shocks. The local shock speed and the transit speed calculated for the results of the magnetohydrodynamic simulation show good agreement with the observations. The relation expressed by the index is well explained by a simplified propagation model assuming a blast wave. For several shocks the ratio is approximately 1.2, implying that these shocks accelerated during propagation in slow-speed solar wind. This ratio is similar to that for the background solar wind acceleration.Keywords. Interplanetary physics (Flare and stream dynamics; Interplanetary shocks; Solar wind plasma)

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>

scholarly journals Dynamics of He++ ions at interplanetary shocks

2020 ◽  
Author(s):  
Olga V. Sapunova ◽  
Natalia L. Borodkova ◽  
Georgii N. Zastenker ◽  
Yuri I. Yermolaev
Keyword(s):  
Solar Wind ◽  
Solar Wind Plasma ◽  
Interplanetary Shock ◽  
Helium Abundance ◽  
Interplanetary Shocks ◽  
Helium Ions ◽  
Wind Instrument ◽  
Absolute Density ◽  
Calculated Velocity ◽  
Α Particles

Abstract. Variations of parameters of twice-ionized helium ions – He++ ions or α-particles – in the solar wind plasma during the interplanetary shock front passage are investigated. We used the data measured by the BMSW (Bright Monitor of Solar Wind) instrument installed on the SPEKTR-R satellite, which operated since August 2011 to 2019 and registered 57 interplanetary shocks. According to received data, the parameters of He++ ions were calculated: velocity Vα, temperature Tα, absolute density Nα and relative density (helium abundance) Nα/Np. The correlation of changes in helium abundance Nα/Np with the parameters βi, θBn and MMS were investigated.

scholarly journals Influence of He++ and shock geometry on interplanetary shocks in the solar wind: 2D Hybrid simulations

2020 ◽  
Author(s):  
Luis Preisser ◽  
Xochitl Blanco-Cano ◽  
Domenico Trotta ◽  
David Burgess ◽  
Primoz Kajdic
Keyword(s):  
Solar Wind ◽  
Velocity Distribution Function ◽  
Interplanetary Shock ◽  
Alpha Particles ◽  
Upstream Region ◽  
Interplanetary Shocks ◽  
Temperature Anisotropy ◽  
Ion Species ◽  
The Magnetic Field ◽  
Hybrid Simulations

<p>Alpha particles (He<sup>++</sup>) are the most important minor ion species in the solar wind, constituting typically about 5% of the total ion number density. When crossing an interplanetary shock protons and He<sup>++</sup> particles are accelerated differently due to their different charge-to-mass ratio. This behavior can produce changes in the velocity distribution function (VDF) for both species in the immediate downstream region generating anisotropy in the temperature which is considered to be the energy source for various phenomena such as ion cyclotron and mirror mode waves for example. How these changes in temperature anisotropy and shock structure depend on the percentage of He<sup>++</sup> particles and the geometry of the shock is not completely understood. In this work we perform various 2D local hybrid simulations (particle ions, massless fluid electrons) with similar characteristics (e.g., Mach number) to observed interplanetary shocks for both quasi-parallel and quasi-perpendicular geometries including self-consistently different percentages of He<sup>++</sup> particles. We find that the change of the initial θ<sub>Bn</sub> leads to variations of the efficiency with which particles can escape to the upstream region facilitating or not the formation of compressive structures in the magnetic field that will produce increments in perpendicular temperature. The regions where both temperature anisotropy and compressive fluctuations appear tend to be more extended and reach higher values as the He<sup>++</sup> content in the simulations increase.</p>

A Brief Review of Previous Studies on Regularity of Stress Waves Propagation in Micro-Cracks of Rock

2012 ◽  
Vol 170-173 ◽  
pp. 511-515
Author(s):  
Jin Yu ◽  
Yan Yan Cai ◽  
Bo Xue Song ◽  
Xu Chen
Keyword(s):  
Wave Propagation ◽  
Stress Wave ◽  
Mathematic Model ◽  
Practical Significance ◽  
Theoretical Interpretation ◽  
Stress Wave Propagation ◽  
Micro Cracks ◽  
Propagation Law ◽  
Mechanism Research ◽  
Long Time

The research of stress wave propagation law under cracked rock has important theoretical value and practical significance. Because of the discontinuity, nonelasticity and nonlinearity of the cracks, the theoretical interpretation and mechanism research about tress wave propagation law are a great challenge to researchers for a long time. From the establishment of the research method, the determination of mathematic model of micro-cracks and the main solutions, this paper brief reviews the current development of the influence of the complicated micro-cracks on stress wave propagation law.

Calculation of Technical Characteristics of the Technical Fleet Vessels Involved in Ensuring Safety of the Offshore Facilities of Oil and Gas Complex

2021 ◽  
pp. 7-13
Author(s):  
S.V. Matsenko ◽  
◽  
V.M. Minko ◽  
A.A. Koshelev ◽  
V.Yu. Piven ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Oil Pollution ◽  
Raw Materials ◽  
Experimental Studies ◽  
Industrial Safety ◽  
Theoretical Studies ◽  
Physical Processes ◽  
Oil Spill Response ◽  
Sea Area

Violation of industrial safety rules during the operation of offshore facilities for the production, storage and transportation of the hydrocarbon raw materials leads in the most cases to pollution of the marine environment with oil and its components. The works on localization and elimination of such pollution are carried out with the help of vessels of the technical support fleet and booms. When developing oil spill response plans at such facilities, a calculated determination of the technical characteristics of vessels and booms is required that are sufficient to carry out the planned activities. The basic design principles for determining the towing capacity of the technical fleet vessels involved in the localization and elimination of oil and oil product spills by trawling methods are given in the article. The calculation is based on theoretical studies performed by the authors of the physical processes occurring during the movement of objects of a mobile trawling order in the sea area. The results obtained during the course of theoretical studies were confirmed by the experimental studies carried out by the authors personally using the real pieces of equipment in the actual development of tasks for training spill containment by trawling. As a result, the empirical dependencies were obtained and experimentally confirmed, which can be used to calculate technical characteristics of the ships as part of the mobile orders and anchor systems as part of stationary orders intended for the localization and elimination of oil pollution. These results can be used, among other things, for the calculated substantiation of the technical characteristics of the technical fleet vessels designed to ensure safety of the offshore facilities for production, storage, and transportation of the hydrocarbon raw materials.

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