scholarly journals Titan's magnetic field signature during the Cassini T34 flyby: Comparison between hybrid simulations and MAG data

2008 ◽  
Vol 35 (4) ◽  
Author(s):  
S. Simon ◽  
U. Motschmann ◽  
G. Kleindienst ◽  
K.-H. Glassmeier ◽  
C. Bertucci ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Hybrid Simulations

Plasma instabilities driven by pickup ions of ring-beam velocity distributions in the outer heliosheath 

2021 ◽  
Author(s):  
Ameneh Mousavi ◽  
Kaijun Liu ◽  
Sina Sadeghzadeh
Keyword(s):  
Magnetic Field ◽  
Maximum Growth ◽  
Dispersion Analysis ◽  
Maximum Growth Rate ◽  
Injection Velocity ◽  
Plasma Instabilities ◽  
Pickup Ions ◽  
Beam Velocity ◽  
Background Magnetic Field ◽  
Hybrid Simulations

<p><span>The stability of the pickup ions in the outer heliosheath has been studied by many researchers because of its relevance to the energetic neutral atom (ENA) ribbon observed by the Interstellar Boundary EXplorer. However, previous studies are primarily limited to pickup ions of near </span><span>90° </span><span>pickup angles, the angle between the pickup ion injection velocity and the background, local interstellar magnetic field. Investigations on pickup ions of smaller pickup angles are still lacking. In this paper, linear kinetic dispersion analysis and hybrid simulations are carried out to examine the plasma instabilities driven by pickup ions of ring-beam velocity distributions at various pickup angles between zero and </span><span>90°</span><span>. </span><span>Parallel propagating waves are studied in the parameter regime where the parallel thermal spread of the pickup ions falls into the Alfvén cyclotron stability gap. </span><span>The linear analysis results and hybrid simulations both show that the fastest growing modes are the right-hand helicity waves propagating in the direction of the background magnetic field, and the maximum growth rate occurs at the pickup angle of </span><span>82°</span><span>. The simulation results further reveal that the saturation level of the fluctuating magnetic fields for pickup angles below </span><span>45° </span><span>is higher than that for pickup angles above </span><span>45°</span><span>. So, the scattering of pickup ions at near zero pickup angles is likely more pronounced than that at near </span><span>90° </span><span>pickup angles</span> .</p>

Feasibility study of an adaptive mount system based on magnetorheological elastomer using real-time hybrid simulation

2018 ◽  
Vol 30 (5) ◽  
pp. 701-707 ◽  
Author(s):  
Seung-Hyun Eem ◽  
Jeong-Hoi Koo ◽  
Hyung-Jo Jung
Keyword(s):  
Magnetic Field ◽  
Control System ◽  
Real Time ◽  
Control Algorithm ◽  
Vibration Reduction ◽  
Hybrid Simulation ◽  
Shaking Table ◽  
Magnetorheological Elastomer ◽  
Experimental Part ◽  
Hybrid Simulations

This article investigates an adaptive mount system based on magnetorheological elastomer in reducing the vibration of an equipment on the isolation table. Incorporating MR elastomers, whose elastic modulus or stiffness can be adjusted depending on the applied magnetic field, the proposed mount system strives to alleviate the limitations of existing passive-type mount systems. The primary goal of this study is to evaluate the vibration reduction performance of the proposed MR elastomer mount using the hybrid simulation technique. For real-time hybrid simulations, the MR elastomer mount and the control system are used as an experimental part, which is installed on the shaking table, and an equipment on the table is used as a numerical part. A suitable control algorithm is designed for the real-time hybrid simulations to avoid the responses of the equipment’s natural frequency by tracking the frequencies of the responses. After performing a series of real-time hybrid simulation on the adaptive mount system and the passive-type mount system under sinusoidal excitations, this study compares the effectiveness of the adaptive mount system over its passive counterpart. The results show that the proposed adaptive elastomer mount system outperforms the passive-type mount system in reducing the responses of the equipment for the excitations considered in this study.

scholarly journals Hybrid simulations of EMIC waves in a dipolar magnetic field

2011 ◽  
Vol 116 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. Omidi ◽  
R. Thorne ◽  
J. Bortnik
Keyword(s):  
Magnetic Field ◽  
Emic Waves ◽  
Hybrid Simulations

scholarly journals Aspects of solar wind interaction with Mars: comparison of fluid and hybrid simulations

2007 ◽  
Vol 25 (1) ◽  
pp. 145-159
Author(s):  
N. V. Erkaev ◽  
A. Bößwetter ◽  
U. Motschmann ◽  
H. K. Biernat
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Hybrid Model ◽  
Field Enhancement ◽  
Bow Shock ◽  
Solar Wind Interaction ◽  
Plasma Parameters ◽  
Physical Reason ◽  
The Magnetic Field ◽  
Hybrid Simulations

Abstract. Mars has no global intrinsic magnetic field, and consequently the solar wind plasma interacts directly with the planetary ionosphere. The main factors of this interaction are: thermalization of plasma after the bow shock, ion pick-up process, and the magnetic barrier effect, which results in the magnetic field enhancement in the vicinity of the obstacle. Results of ideal magnetohydrodynamic and hybrid simulations are compared in the subsolar magnetosheath region. Good agreement between the models is obtained for the magnetic field and plasma parameters just after the shock front, and also for the magnetic field profiles in the magnetosheath. Both models predict similar positions of the proton stoppage boundary, which is known as the ion composition boundary. This comparison allows one to estimate applicability of magnetohydrodynamics for Mars, and also to check the consistency of the hybrid model with Rankine-Hugoniot conditions at the bow shock. An additional effect existing only in the hybrid model is a diffusive penetration of the magnetic field inside the ionosphere. Collisions between ions and neutrals are analyzed as a possible physical reason for the magnetic diffusion seen in the hybrid simulations.

Effects of the Solar Wind Conditions on Mercury's Exosphere: Hybrid Simulations

2020 ◽  
Author(s):  
Pavel M. Travnicek ◽  
Dave Schriver ◽  
Thomas Orlando ◽  
James A. Slavin
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Dynamic Pressure ◽  
Energy Levels ◽  
Solar Wind Plasma ◽  
Deposited Energy ◽  
Solar Wind Parameters ◽  
Primary Focus ◽  
Hybrid Simulations

<pre class="western">We carry out a set of global hybrid simulations of the Mercury's magnetosphere with the interplanetary magnetic field oriented in the desired directions. <br />We study effects of changes of different solar wind parameters on the structure of the plasma circulation within Mercury’s magnetosphere. We focus our <br />study on the changes caused by changes in the orientation of the interplanetary magnetic field and the dynamic pressure (velocity) of the solar wind. <br />We study the structure of the of the Mercury’s magnetosphere under different solar wind conditions. Our primary focus is the assessment of the <br />precipitation levels of solar wind hydrogen on the Mercury's surface (the amount, the deposited energy, its spectra and angular distribution) and on the <br />formation of Mercury's exosphere. We examine density fluxes, energy levels and spectra of protons precipitating on Mercury’s surface as a function of <br />longitude and altitude. It has been established, that Mercury has a plasma belt formed by quasi-trapped solar wind plasma close to the Mercury’s surface. <br />Charged particles trapped in the belt mostly circle Mercury 1-2 times before they either precipitate on Mercury’s surface or escape into the Mercury’s <br />magnetospheric cavity. Lower dynamic pressure of the solar wind pushes magnetopause up above the Mercury’s surface and the plasma belt has more <br />space to develop. Its interaction with Mercury’s surface and dynamics under different solar wind conditions is essential on the precipitation of the plasma <br />on the Mercury’s surface. Higher dynamic pressure of the solar wind can push the bow shock towards Mercury’s surface and make the surface open to the <br />direct impact of the solar wind on the Mercury’s surface. Due to weak magnetic moment of the Mercury’s magnetosphere, the plasma environment at Mercury <br />is very dynamic.</pre>

scholarly journals Rosetta swing-by at Mars – an analysis of the ROMAP measurements in comparison with results of 3-D multi-ion hybrid simulations and MEX/ASPERA-3 data

2009 ◽  
Vol 27 (6) ◽  
pp. 2383-2398 ◽  
Author(s):  
A. Boesswetter ◽  
U. Auster ◽  
I. Richter ◽  
M. Fränz ◽  
B. Langlais ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Bow Shock ◽  
Gravity Assist ◽  
Pile Up ◽  
Magnetic Field Model ◽  
Order Of Magnitude ◽  
Upstream Waves ◽  
Insight Into ◽  
Hybrid Simulations

Abstract. The Rosetta spacecraft flew by Mars at a distance of 260 km on 25 February 2007 during a gravity assist manoeuvre. During the closest approach (CA) the lander magnetometer ROMAP was switched on. The dataset taken during this swingby provides insight into the plasma environment around Mars: in addition to a pronounced bow shock crossing Rosetta recorded the signature of the pile up region of draped magnetic field. Also the Rosetta measurements showed signatures of crustal magnetic field anomalies which can be verified by results of a crustal magnetic field model. In order to understand the measured field morphology, multi-ion hybrid simulations were performed. Some of the input parameters for the simulations were obtained from Mars Express (MEX) data which were contemporaneously collected during the Rosetta swingby. These simulations reproduces ROMAP magnetic field measurements and show that the interplanetary magnetic field pointed northward during the encounter. A spectral analysis shows upstream waves ahead of the bow shock and indicates the presence of the magnetic pile-up boundary (MPB). The multi-ion model reproduces the ion fluxes measured by MEX/ASPERA-3 and is in agreement with the measurements to within one order of magnitude.

Magnetic-field strengths from optical polarization data

1967 ◽  
Vol 31 ◽  
pp. 381-383
Author(s):  
J. M. Greenberg
Keyword(s):  
Magnetic Field ◽  
Optical Polarization ◽  
Polarization Data ◽  
Term Model ◽  
Source Of Information ◽  
Field Strengths

Van de Hulst (Paper 64, Table 1) has marked optical polarization as a questionable or marginal source of information concerning magnetic field strengths. Rather than arguing about this–I should rate this method asq+-, or quarrelling about the term ‘model-sensitive results’, I wish to stress the historical point that as recently as two years ago there were still some who questioned that optical polarization was definitely due to magnetically-oriented interstellar particles.

Observing the galactic magnetic field

1967 ◽  
Vol 31 ◽  
pp. 375-380
Author(s):  
H. C. van de Hulst
Keyword(s):  
Magnetic Field ◽  
Fair Agreement ◽  
Solar Neighbourhood ◽  
Galactic Magnetic Field ◽  
The Magnetic Field

Various methods of observing the galactic magnetic field are reviewed, and their results summarized. There is fair agreement about the direction of the magnetic field in the solar neighbourhood:l= 50° to 80°; the strength of the field in the disk is of the order of 10-5gauss.

Sign in / Sign up

Export Citation Format

Share Document