On the Bow-Shock dynamics in response to a Quasi-Perpendicular interaction with different Solar Wind conditions

2021 ◽  
Author(s):  
Emanuele Cazzola ◽  
Dominique Fontaine ◽  
Philippe Savoini
Keyword(s):  
Solar Wind ◽  
Computer Simulations ◽  
Cross Sections ◽  
Ad Hoc ◽  
Three Dimensional ◽  
Bow Shock ◽  
Hybrid Code ◽  
Mach Numbers ◽  
The Imf

<p>This work will be giving new insights into the global Quasi-Perpendicular interaction effects of the Solar Wind with a realistic three-dimensional terrestrial-like curved Bow Shock (BS) by means of hybrid computer simulations.<br>The Bow-Shock profoundly changes its behavior for different incoming Solar Wind conditions. For Alfvénic Mach numbers greater than a specific threshold, the Bow-Shock shows an intense rippling phenomenon propagating along its surface, as well as the formation of a set of waves in the near-Earth flanks.<br>A similar rippling has been observed from different independent in-situ satellite crossings, as well as studied with ad-hoc computer simulations configured with 2D-planar shocks, conclusively confirming the highly kinetic nature of this phenomenon. Yet, the possible effects of a global three-dimensional curved interaction are still poorly described.<br>As such, we have performed a series of 3D simulations at different Alfvénic Mach numbers, different plasma beta - ratio between the thermal to the magnetic pressures - and different incoming Interplanetary Magnetic Field (IMF) configurations with the hybrid code LatHyS, which was already successfully used for similar past analyses.<br>Particularly, we have found that the ripples follow a pattern not directly driven by the IMF direction as initially expected, but rather a Nose-to-Flanks propagation with the rippling onset region  being significantly displaced from the nose position. Additionally, this phenomenon seems to be mainly confined to the plane on where the IMF direction lies, with the perpendicular cross-sections showing only a slight oscillation.<br>Finally, we have observes a significant ions acceleration in the local perpendicular directions along the flanks modulations, which is most likely related to the local IMF-BS normal fluctuations occurring in the ripples boundary.</p>

scholarly journals Ultra-low-frequency waves in the ion foreshock of Mercury: a global hybrid modelling study

2019 ◽  
Vol 491 (3) ◽  
pp. 4147-4161 ◽  
Author(s):  
R Jarvinen ◽  
M Alho ◽  
E Kallio ◽  
T I Pulkkinen
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Three Dimensional ◽  
Low Frequency ◽  
Bow Shock ◽  
Solar Wind Interaction ◽  
Ulf Wave ◽  
Upstream Condition ◽  
Upstream Solar Wind ◽  
The Imf

ABSTRACT We study the solar wind interaction with Mercury using a global three-dimensional hybrid model. In the analysed simulation run, we find a well-developed, dynamic Hermean ion foreshock ahead of the quasi-parallel bow shock under upstream solar wind and interplanetary magnetic field (IMF) conditions corresponding to the orbital perihelion of the planet. A portion of the incident solar wind ion flux is scattered back upstream near the quasi-parallel bow shock including both major solar wind ion species, protons and alphas. The scattered particles form the Hermean suprathermal foreshock ion population. A significant part of the suprathermal population is backstreaming with a velocity component towards the Sun in the near-foreshock at the planetocentric distance of few planetary radii in the plane of the IMF. The ion foreshock is associated with large-scale, oblique fast magnetosonic waves in the ultra-low-frequency (ULF) range convecting downstream with the solar wind. The ULF wave period is about 5 s in the analysed upstream condition case at Mercury, which corresponds to the 30-s foreshock waves at Earth when scaled by the IMF magnitude.

scholarly journals Plasma environment of magnetized asteroids: a 3-D hybrid simulation study

2006 ◽  
Vol 24 (1) ◽  
pp. 407-414 ◽  
Author(s):  
S. Simon ◽  
T. Bagdonat ◽  
U. Motschmann ◽  
K.-H. Glassmeier
Keyword(s):  
Solar Wind ◽  
Three Dimensional ◽  
Hybrid Simulation ◽  
Interaction Region ◽  
Bow Shock ◽  
The Other ◽  
Simulation Code ◽  
Kinetic Effects ◽  
Intrinsic Magnetic Moment ◽  
The One

Abstract. The interaction of a magnetized asteroid with the solar wind is studied by using a three-dimensional hybrid simulation code (fluid electrons, kinetic ions). When the obstacle's intrinsic magnetic moment is sufficiently strong, the interaction region develops signs of magnetospheric structures. On the one hand, an area from which the solar wind is excluded forms downstream of the obstacle. On the other hand, the interaction region is surrounded by a boundary layer which indicates the presence of a bow shock. By analyzing the trajectories of individual ions, it is demonstrated that kinetic effects have global consequences for the structure of the interaction region.

scholarly journals A three-dimensional hybrid code simulation of the December 1984 solar wind AMPTE release

1999 ◽  
Vol 26 (18) ◽  
pp. 2837-2840 ◽  
Author(s):  
P. A. Delamere ◽  
D. W. Swift ◽  
H. C. Stenbaek-Nielsen
Keyword(s):  
Solar Wind ◽  
Three Dimensional ◽  
Hybrid Code

scholarly journals First simultaneous measurements of waves generated at the bow shock in the solar wind, the magnetosphere and on the ground

2009 ◽  
Vol 27 (1) ◽  
pp. 357-371 ◽  
Author(s):  
L. B. N. Clausen ◽  
T. K. Yeoman ◽  
R. C. Fear ◽  
R. Behlke ◽  
E. A. Lucek ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cone Angle ◽  
Bow Shock ◽  
Wave Power ◽  
Sudden Increase ◽  
Model Predictions ◽  
Field Lines ◽  
Upstream Waves ◽  
The Imf

Abstract. On 5 September 2002 the Geotail satellite observed the cone angle of the Interplanetary Magnetic Field (IMF) change to values below 30° during a 56 min interval between 18:14 and 19:10 UT. This triggered the generation of upstream waves at the bow shock, 13 RE downstream of the position of Geotail. Upstream generated waves were subsequently observed by Geotail between 18:30 and 18:48 UT, during times the IMF cone angle dropped below values of 10°. At 18:24 UT all four Cluster satellites simultaneously observed a sudden increase in wave power in all three magnetic field components, independent of their position in the dayside magnetosphere. We show that the 10 min delay between the change in IMF direction as observed by Geotail and the increase in wave power observed by Cluster is consistent with the propagation of the IMF change from the Geotail position to the bow shock and the propagation of the generated waves through the bow shock, magnetosheath and magnetosphere towards the position of the Cluster satellites. We go on to show that the wave power recorded by the Cluster satellites in the component containing the poloidal and compressional pulsations was broadband and unstructured; the power in the component containing toroidal oscillations was structured and shows the existence of multi-harmonic Alfvénic continuum waves on field lines. Model predictions of these frequencies fit well with the observations. An increase in wave power associated with the change in IMF direction was also registered by ground based magnetometers which were magnetically conjunct with the Cluster satellites during the event. To the best of our knowledge we present the first simultaneous observations of waves created by backstreaming ions at the bow shock in the solar wind, the dayside magnetosphere and on the ground.

scholarly journals The Global Interaction of Comets with the Solar Wind

1991 ◽  
Vol 116 (2) ◽  
pp. 1125-1144 ◽  
Author(s):  
K. R. Flammer
Keyword(s):  
Solar Wind ◽  
Heliocentric Distance ◽  
Theoretical Models ◽  
Bow Shock ◽  
Flow Transition ◽  
The Sun ◽  
In Situ Observations ◽  
Comet Halley

AbstractThe global interaction of the solar wind with a comet as it orbits the Sun is reviewed. After a brief survey of the flow transition regions observed at comet Halley is presented, theoretical models are given for the cometocentric distance of the bow shock, the cometopause, and the ionopause. In addition, predictions are made as to what heliocentric distance these boundaries should form at. The results of these models are compared with the in situ observations at comet Halley.

scholarly journals Asymmetries in the Earth's dayside magnetosheath: results from global hybrid-Vlasov simulations

2020 ◽  
Author(s):  
Lucile Turc ◽  
Vertti Tarvus ◽  
Andrew Dimmock ◽  
Markus Battarbee ◽  
Urs Ganse ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Mach Number ◽  
Field Strength ◽  
Flow Velocity ◽  
Magnetic Field Strength ◽  
Bow Shock ◽  
Wide Range ◽  
The Magnetic Field ◽  
The Imf

<p>The magnetosheath is the region bounded by the bow shock and the magnetopause which is home to shocked solar wind plasma. At the interface between the solar wind and the magnetosphere, the magnetosheath plays a key role in the coupling between these two media. Previous works have revealed pronounced dawn-dusk asymmetries in the magnetosheath properties, with for example the magnetic field strength and flow velocity being larger on the dusk side, while the plasma is denser, hotter and more turbulent on the dawn side. The dependence of these asymmetries on the upstream parameters remains however largely unknown. One of the main sources of these asymmetries is the bow shock configuration, which is typically quasi-parallel on the dawn side and quasi-perpendicular on the dusk side of the terrestrial magnetosheath because of the Parker-spiral orientation of the interplanetary magnetic field (IMF) at Earth. Most of these previous studies rely on collections of spacecraft measurements associated with a wide range of upstream conditions that have been processed to obtain the average values of the magnetosheath parameters. In this work, we use a different approach and quantify the magnetosheath asymmetries in global hybrid-Vlasov simulations performed with the Vlasiator model. We concentrate on three parameters: the magnetic field strength, the plasma density and the flow velocity. We find that the Vlasiator model reproduces accurately the polarity of the asymmetries, but that their level tends to be higher than in spacecraft measurements, probably due to the different processing methods. We investigate how the asymmetries change when the IMF becomes more radial and when the Alfvén Mach number decreases. When the IMF makes a 30° angle with the Sun-Earth line instead of 45°, we find a stronger magnetic field asymmetry and a larger variability of the magnetosheath density. In contrast, a lower Alfvén Mach number leads to a decrease of the magnetic field asymmetry level and of the variability of the magnetosheath density and velocity, likely due to weaker foreshock processes.</p>

scholarly journals The responses of the earth’s magnetopause and bow shock to the IMF Bz and the solar wind dynamic pressure: a parametric study using the AMR-CESE-MHD model

2018 ◽  
Vol 8 ◽  
pp. A41 ◽  
Author(s):  
Juan Wang ◽  
Zhifang Guo ◽  
Yasong S. Ge ◽  
Aimin Du ◽  
Can Huang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Mach Number ◽  
Dynamic Pressure ◽  
Bow Shock ◽  
Solar Wind Dynamic Pressure ◽  
The Earth ◽  
Shock Location ◽  
Mhd Model ◽  
Upstream Solar Wind ◽  
The Imf

We have used the AMR-CESE-MHD model to investigate the influences of the IMF Bz and the upstream solar wind dynamic pressure (Dp) on Earth’s magnetopause and bow shock. Our results present that the earthward displacement of the magnetopause increases with the intensity of the IMF Bz. The increase of the northward IMF Bz also brings the magnetopause closer to the Earth even though with a small distance. Our simulation results show that the subsolar bow shock during the southward IMF is much closer to the Earth than during the northward IMF. As the intensity of IMF Bz increases (also the total field strength), the subsolar bow shock moves sunward as the solar wind magnetosonic Mach number decreases. The sunward movement of the subsolar bow shock during southward IMF are much smaller than that during northward IMF, which indicates that the decrease of solar wind magnetosonic Mach number hardly changes the subsolar bow shock location during southward IMF. Our simulations also show that the effects of upstream solar wind dynamic pressure (Dp) changes on both the subsolar magnetopause and bow shock locations are much more significant than those due to the IMF changes, which is consistent with previous studies. However, in our simulations the earthward displacement of the subsolar magnetopause during high solar wind Dp is greater than that predicted by the empirical models.

scholarly journals Solar wind charge exchange in cometary atmospheres

2019 ◽  
Vol 630 ◽  
pp. A37 ◽  
Author(s):  
Cyril Simon Wedlund ◽  
Etienne Behar ◽  
Hans Nilsson ◽  
Markku Alho ◽  
Esa Kallio ◽  
...  
Keyword(s):  
Solar Wind ◽  
Charge Exchange ◽  
Cross Sections ◽  
Extreme Ultraviolet ◽  
Solar Wind Plasma ◽  
Analytical Models ◽  
Sharp Drop ◽  
Solar Wind Charge Exchange ◽  
Comet 67P

Context. Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet. The ESA/Rosetta mission to comet 67P/Churyumov-Gerasimenko (67P) provides a unique opportunity to study charge-changing processes in situ. Aims. To understand the role of these reactions in the evolution of the solar wind plasma and interpret the complex in situ measurements made by Rosetta, numerical or analytical models are necessary. Methods. We used an extended analytical formalism describing solar wind charge-changing processes at comets along solar wind streamlines. The model is driven by solar wind ion measurements from the Rosetta Plasma Consortium-Ion Composition Analyser (RPC-ICA) and neutral density observations from the Rosetta Spectrometer for Ion and Neutral Analysis-Comet Pressure Sensor (ROSINA-COPS), as well as by charge-changing cross sections of hydrogen and helium particles in a water gas. Results. A mission-wide overview of charge-changing efficiencies at comet 67P is presented. Electron capture cross sections dominate and favor the production of He and H energetic neutral atoms (ENAs), with fluxes expected to rival those of H+ and He2+ ions. Conclusions. Neutral outgassing rates are retrieved from local RPC-ICA flux measurements and match ROSINA estimates very well throughout the mission. From the model, we find that solar wind charge exchange is unable to fully explain the magnitude of the sharp drop in solar wind ion fluxes observed by Rosetta for heliocentric distances below 2.5 AU. This is likely because the model does not take the relative ion dynamics into account and to a lesser extent because it ignores the formation of bow-shock-like structures upstream of the nucleus. This work also shows that the ionization by solar extreme-ultraviolet radiation and energetic electrons dominates the source of cometary ions, although solar wind contributions may be significant during isolated events.

scholarly journals On the edge of the foreshock: model-data comparisons

2008 ◽  
Vol 26 (6) ◽  
pp. 1539-1544 ◽  
Author(s):  
D. G. Sibeck ◽  
N. Omidi ◽  
I. Dandouras ◽  
E. Lucek
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Large Amplitude ◽  
Bow Shock ◽  
Model Data ◽  
Solar Wind Interaction ◽  
Hybrid Code ◽  
Amplitude Density

Abstract. We present the results of a global hybrid code simulation for the solar wind-interaction with the Earth's magnetosphere during an interval of steady radial IMF. The model predicts a foreshock marked by innumerable localized, correlated, and large amplitude, density and magnetic field strength variations, depressed velocities, and enhanced temperatures. The foreshock is bounded by a broad (~0.8 RE) region of enhanced densities, temperatures, and magnetic field strengths that extends far (~8.6 RE) upstream from the bow shock. Flow perturbations within the boundary are directed perpendicular to the boundary, towards the unperturbed solar wind and away from the foreshock. Cluster observations of the ion foreshock and pristine solar wind confirm the predictions of the model. The observations suggest that foreshock cavities, crater-like density and magnetic field strength structures whose cores are filled with suprathermal particles, can be interpreted in terms of transient encounters with the foreshock boundary.

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