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- Creator:
- Xiantong Wang
- Description:
- We perform a geomagnetic event simulation using a newly developed magnetohydrodynamic with adaptively embedded particle-in-cell (MHD-AEPIC) model. We have developed effective criteria to identify reconnection sites in the magnetotail and cover them with the PIC model. The MHD-AEPIC simulation results are compared with Hall MHD and ideal MHD simulations to study the impacts of kinetic reconnection at multiple physical scales. At the global scale, the three models produce very similar SYM-H and SuperMag Electrojet (SME) indexes, which indicates that the global magnetic field configurations from the three models are very close to each other. At the mesoscale we compare the simulations with in situ Geotail observations in the tail. All three models produce reasonable agreement with the Geotail observations. The MHD-AEPIC and Hall MHD models produce tailward and earthward propagating fluxropes, while the ideal MHD simulation does not generate flux ropes in the near-earth current sheet. At the kinetic scales, the MHD-AEPIC simulation can produce a crescent shape distribution of the electron velocity space at the electron diffusion region which agrees very well with MMS observations near a tail reconnection site. These electron scale kinetic features are not available in either the Hall MHD or ideal MHD models. Overall, the MHD-AEPIC model compares well with observations at all scales, it works robustly, and the computational cost is acceptable due to the adaptive adjustment of the PIC domain.
- Keyword:
- MHD, PIC, and Magnetosphere
- Discipline:
- Science
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- Creator:
- Chen, Yuxi
- Description:
- We use the MHD with embedded particle-in-cell model (MHD-EPIC) to study the Geospace Environment Modeling (GEM) dayside kinetic processes challenge event at 01:50-03:00 UT on 2015-11-18, when the magnetosphere was driven by a steady southward IMF. In the MHD-EPIC simulation, the dayside magnetopause is covered by a PIC code so that the dayside reconnection is properly handled. We compare the magnetic fields and the plasma profiles of the magnetopause crossing with the MMS3 spacecraft observations. Most variables match the observations well in the magnetosphere, in the magnetosheath, and also during the current sheet crossing. The MHD-EPIC simulation produces flux ropes, and we demonstrate that some magnetic field and plasma features observed by the MMS3 spacecraft can be reproduced by a flux rope crossing event. We use an algorithm to automatically identify the reconnection sites from the simulation results. It turns out that there are usually multiple X-lines at the magnetopause. By tracing the locations of the X-lines, we find the typical moving speed of the X-line endpoints is about 70~km/s, which is higher than but still comparable with the ground-based observations.
- Keyword:
- MHD, PIC, and simulation
- Citation to related publication:
- Chen, Y., Tóth, G., Hietala, H., Vines, S. K., Zou, Y., Nishimura, Y., Silveira, M. V. D., Guo, Z., Lin, Y., & Markidis, S. (2020). Magnetohydrodynamic With Embedded Particle-In-Cell Simulation of the Geospace Environment Modeling Dayside Kinetic Processes Challenge Event. Earth and Space Science, 7(11), e2020EA001331. https://doi.org/10.1029/2020EA001331 and Chen, Yuxi, et al. "Magnetohydrodynamic with embedded particle-in-cell simulation of the Geospace Environment Modeling dayside kinetic processes challenge event." arXiv preprint arXiv:2001.04563 (2020). https://arxiv.org/abs/2001.04563
- Discipline:
- Science
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- Creator:
- Zhou, Hongyang
- Description:
- The largest moon in the solar system, Ganymede, is the only moon known to possess a strong intrinsic magnetic field and a corresponding magnetosphere. Using the latest version of Space Weather Modeling Framework (SWMF), we study the upstream plasma interactions and dynamics in this sub-Alfvenic system. Results from the Hall MHD and the coupled MHD with embedded Particle-in-Cell (MHD-EPIC) models are compared. We find that under steady upstream conditions, magnetopause reconnection occurs in a non-steady manner. Flux ropes of Ganymede's radius in length form on the magnetopause at a rate about 2/minute and create spatiotemporal variations in plasma and field properties. Upon reaching proper grid resolutions, the MHD-EPIC model can resolve both electron and ion kinetics at the magnetopause and show localized non-gyrotropic behavior inside the diffusion region. The estimated global reconnection rate from the models is about 80 kV with 60% efficiency, and there is weak evidence of about 1 minute periodicity in the temporal variations due to the dynamic reconnection process.
- Keyword:
- MHD, PIC, Ganymede, and magnetosphere
- Citation to related publication:
- Zhou, H., Tóth, G., Jia, X., & Chen, Y. (2020). Reconnection-Driven Dynamics at Ganymede’s Upstream Magnetosphere: 3-D Global Hall MHD and MHD-EPIC Simulations. Journal of Geophysical Research: Space Physics, 125(8), e2020JA028162. https://doi.org/10.1029/2020JA028162
- Discipline:
- Science
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- Creator:
- Wang, Zihan
- Description:
- SWMF is used to study the segmentation of SED plume into polar cap patches during the geomagnetic storm on Sep 7, 2017. The database includes the 3D output in the upper atmosphere from GITM, the 2D output from Ionospheric Electrodynamics (IE) and 3D output from BATSRUS. The output from GITM can be read with thermo_batch_new.pro. The output from IE can be opened with Spacepy at https://pythonhosted.org/SpacePy/. The output from BATSRUS can be opened with tecplot. More details can be found in Readme.txt.
- Keyword:
- MHD and Ionosphere
- Citation to related publication:
- Wang, Z., Zou, S., Coppeans, T., Ren, J., Ridley, A., & Gombosi, T. (2019). Segmentation of SED by Boundary Flows Associated With Westward Drifting Partial Ring current. Geophysical Research Letters, 46(14), 7920–7928. https://doi.org/10.1029/2019GL084041
- Discipline:
- Science
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- Creator:
- Hongyang Zhou
- Description:
- The outputs include the steady state solutions for all Galileo flybys, the particle information for plotting the distribution functions near the reconnection site, the particle and field data for mapping the energetic flux densities, and 3D files for visualizing the whole simulation domain. More details can be found in Readme.txt.
- Keyword:
- MHD and PIC
- Citation to related publication:
- Zhou, H., Tóth, G., Jia, X., Chen, Y., & Markidis, S. (2019). Embedded kinetic simulation of Ganymede's magnetosphere: Improvements and inferences. Journal of Geophysical Research: Space Physics, 124, 5441– 5460. https://doi.org/10.1029/2019JA026643
- Discipline:
- Science
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- Creator:
- Ozturk, Dogacan S
- Description:
- The modeling research conducted to produce this dataset focuses on the solar wind dynamic pressure drop events and how they affect the Earth's intrinsically coupled Magnetosphere, Ionosphere and Thermosphere systems. This study specifically focuses on the 11 June 2017 event, where the solar wind dynamic pressure dropped significantly following a period of higher pressure. We model the response to this pressure drop using University of Michigan Space Weather Modeling Framework ( http://csem.engin.umich.edu/tools/swmf/). The simulation results were created using BATS-R-US and GITM models. The observational data required for model comparisons were taken from OMNI ( https://omniweb.gsfc.nasa.gov) and CDAWeb ( https://cdaweb.gsfc.nasa.gov/sp_phys/) Databases.
- Keyword:
- GITM, BATS-R-US, Solar wind dynamic pressure, Magnetosphere-Ionosphere-Thermosphere, and MHD
- Citation to related publication:
- Ozturk, D. S., Zou, S., Slavin, J. A., & Ridley, A. J. ( 2019). Response of the geospace system to the solar wind dynamic pressure decrease on 11 June 2017: Numerical models and observations. Journal of Geophysical Research: Space Physics, 124, 2613– 2627. https://doi.org/10.1029/2018JA026315
- Discipline:
- Science
-
- Creator:
- Regoli, Leonardo H.
- Description:
- The data corresponds to outputs from the Mars Global Ionosphere Thermosphere Model (M-GITM), the multi-species magnetohydrodynamics (MS-MHD) and multi-fluid magnetohydrodynamics (MF-MHD) codes used during the study presented in "Multi-species and multi-fluid MHD approaches for the study of ionospheric escape at Mars" by Regoli et al. and Dataset citation: Regoli, L.H. (2018). Model outputs for "Multi-species and multi-fluid MHD approaches for the study of ionospheric escape at Mars" [Data set]. University of Michigan Deep Blue Data Repository. https://doi.org/10.7302/Z2GH9G49
- Keyword:
- GCM, MHD, and Mars
- Citation to related publication:
- Regoli, L.H., Dong, C., Ma, Y.J., Dubinin, E., Manchester, W.B., Bougher, S.W., & Welling, D.T. (2018). Multispecies and multifluid MHD approaches for the study of ionospheric escape at Mars. Journal of Geophysical Research: Space Physics, 123. https://doi.org/10.1029/2017JA025117
- Discipline:
- Science