A fast bow shock location predictor-estimator from 2D and 3D analytical models: Application to Mars and the MAVEN mission

A comparison between different analytical and finite-element (FE) tools for the computation of cogging torque and torque ripple in axial flux permanent-magnet synchronous machines is made. 2D and 3D FE models are the most accurate for the computation of cogging torque and torque ripple. However, they are too time consuming to be used for optimization studies. Therefore, analytical tools are also used to obtain the cogging torque and torque ripple. In this paper, three types of analytical models are considered. They are all based on dividing the machine into many slices in the radial direction. One model computes the lateral force based on the magnetic field distribution in the air gap area. Another model is based on conformal mapping and uses complex Schwarz Christoffel (SC) transformations. The last model is based on the subdomain technique, which divides the studied geometry into a number of separate domains. The different types of models are compared for different slot openings and permanent-magnet widths. One of the main conclusions is that the subdomain model is best suited to compute the cogging torque and torque ripple with a much higher accuracy than the SC model.

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Electric current systems at Mars and Venus

10.5194/epsc2020-1017 ◽

2020 ◽

Author(s):

Markus Fränz ◽

Eduard Dubinin ◽

Lukas Maes

Keyword(s):

Solar Wind ◽

Electric Current ◽

Dynamic Models ◽

Bow Shock ◽

Dynamic Effects ◽

Current Configuration ◽

Ion Escape ◽

Shock Location ◽

Physical Effects ◽

Current Systems

The physics of the interaction of unmagnetized planets with the Solar wind has been investigated since the first Mariner spacecraft did reach Mars and Venus more than 50 years ago. Recent observations of the magnetic fields at Mars allowed&#160; to derive the global electric current configuration in the Martian system. Earlier magneto hydro-dynamic models were able to predict the formation and location of the bowshock in front of the planets. More sophisticated models&#160; of the interaction with the magnetized solar wind later could demonstrate the global static picture of the plasma environment of Mars and Venus. But earlier models were rarely able to model dynamic effects and the timing of physical process in this interaction. We here use the open source PLUTO code in its 3D spherical hydrodynamic and magneto-hydrodynamic version.&#160; We also develop a multi-species extension of this code.&#160; We investigate the interaction of the solar wind with the ionospheres of Mars and Venus with the aim to understand the&#160; importance of &#160;different physical effects on bow shock location, ion escape and specifically the electric current structures.&#160; We compare these simulations to observations by the VEX and MAVEN spacecraft.

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Estimation of a planetary magnetic field using a reduced magnetohydrodynamic model

Annales Geophysicae ◽

10.5194/angeo-35-465-2017 ◽

2017 ◽

Vol 35 (3) ◽

pp. 465-474

Author(s):

Christian Nabert ◽

Daniel Heyner ◽

Karl-Heinz Glassmeier

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Dipole Moment ◽

Statistical Error ◽

Solar Wind Plasma ◽

Bow Shock ◽

Data Sets ◽

Abstract Knowledge ◽

Planetary Magnetic Fields ◽

Shock Location

Abstract. Knowledge of planetary magnetic fields provides deep insights into the structure and dynamics of planets. Due to the interaction of a planet with the solar wind plasma, a rather complex magnetic environment is generated. The situation at planet Mercury is an example of the complexities occurring as this planet's field is rather weak and the magnetosphere rather small. New methods are presented to separate interior and exterior magnetic field contributions which are based on a dynamic inversion approach using a reduced magnetohydrodynamic (MHD) model and time-varying spacecraft observations. The methods select different data such as bow shock location information or magnetosheath magnetic field data. Our investigations are carried out in preparation for the upcoming dual-spacecraft BepiColombo mission set out to precisely estimate Mercury's intrinsic magnetic field. To validate our new approaches, we use THEMIS magnetosheath observations to estimate the known terrestrial dipole moment. The terrestrial magnetosheath provides observations from a strongly disturbed magnetic environment, comparable to the situation at Mercury. Statistical and systematic errors are considered and their dependence on the selected data sets are examined. Including time-dependent upstream solar wind variations rather than averaged conditions significantly reduces the statistical error of the estimation. Taking the entire magnetosheath data along the spacecraft's trajectory instead of only the bow shock location into account further improves accuracy of the estimated dipole moment.

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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

Journal of Space Weather and Space Climate ◽

10.1051/swsc/2018030 ◽

2018 ◽

Vol 8 ◽

pp. A41 ◽

Cited By ~ 4

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.

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