Results 81 to 90 of about 311 (97)

Ion Acceleration by Foreshock Bubbles

Journal of Geophysical Research: Space Physics, 2021
AbstractForeshock bubbles (FBs) form as a result of the interaction between solar wind discontinuities and backstreaming ion beams in the foreshock. They are carried by the solar wind in the anti‐sunward direction and are associated with high energy ions.
N. Omidi, S. H. Lee, D. G. Sibeck
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Formation and Topology of Foreshock Bubbles

Journal of Geophysical Research: Space Physics, 2020
AbstractWe use global and local hybrid (kinetic ions and fluid electrons) simulations to investigate the conditions under which foreshock bubbles (FBs) form and how their topology changes with solar wind conditions. FBs form as a result of the interaction between solar wind discontinuities and backstreaming ion beams in the foreshock.
N. Omidi, S. H. Lee, D. G. Sibeck, D. L. Turner, T. Z. Liu, V. Angelopoulos   +5 more
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Modeling the Expansion Speed of Foreshock Bubbles

Journal of Geophysical Research: Space Physics, 2023
AbstractForeshock transients, including hot flow anomalies (HFAs) and foreshock bubbles (FBs), are frequently observed in the ion foreshock. Their significant dynamic pressure perturbations can disturb the bow shock, resulting in disturbances in the magnetosphere and ionosphere.
Terry Z. Liu, Andrew Vu, Hui Zhang, Xin An, Vassilis Angelopoulos   +4 more
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Foreshock Bubbles at Venus: Hybrid Simulations and VEX Observations

Journal of Geophysical Research: Space Physics, 2020
AbstractIn the absence of a global magnetic field at Venus, its ionosphere is the obstacle to the flow of the solar wind resulting in the formation of a smaller bow shock and foreshock. Spacecraft observations and global hybrid (kinetic ions, fluid electrons) simulations have demonstrated that despite its smaller size, the foreshock at Venus has ...
N. Omidi, G. Collinson, D. Sibeck
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Comparison of MMS Observations of Foreshock Bubbles With a Global Hybrid Simulation

Journal of Geophysical Research: Space Physics, 2021
AbstractWe present multi‐point observations of foreshock bubbles (FBs) for comparison with the predictions of hybrid simulations. The four Magnetospheric Multiscale (MMS) spacecraft observed a series of discontinuities in the region upstream from the bow shock on December 18, 2017. Two solar wind discontinuities were associated with fully developed FBs
S. H. Lee, D. G. Sibeck, N. Omidi, M. V. D. Silveira, B. L. Giles, R. B. Torbert, C. T. Russell, H. Wei, J. L. Burch   +8 more
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Parameter Dependencies of Early‐Stage Tangential Discontinuity‐Driven Foreshock Bubbles in Local Hybrid Simulations

Journal of Geophysical Research: Space Physics, 2023
AbstractForeshock bubbles (FBs) are significant foreshock transients that can accelerate particles and disturb the magnetosphere‐ionosphere system. In the kinetic formation model, foreshock ions interact with the discontinuity by performing partial gyrations to generate currents that change the magnetic field topology around the discontinuity. However,
Andrew Vu, Terry Z. Liu, Hui Zhang, Peter Delamere   +3 more
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Foreshock bubbles and their global magnetospheric impacts

Journal of Geophysical Research: Space Physics, 2010
We employ 2.5‐D electromagnetic, hybrid simulations that treat ions kinetically via particle‐in‐cell methods and electrons as a massless fluid to study the formation and properties of a new structure named the foreshock bubble upstream from the bow shock.
N. Omidi, J. P. Eastwood, D. G. Sibeck
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Statistical Study of Foreshock Bubbles, Hot Flow Anomalies, and Spontaneous Hot Flow Anomalies and Their Substructures Observed by MMS

Journal of Geophysical Research: Space Physics, 2022
AbstractForeshock transients such as foreshock bubbles (FBs), hot flow anomalies (HFAs), and spontaneous hot flow anomalies (SHFAs) display heated, tenuous cores and large flow deflections bounded by compressional boundaries. THEMIS and Cluster observations show that some cores contain local density enhancements which can be studied to better ...
Andrew Vu, Terry Z. Liu, Hui Zhang, Craig Pollock   +3 more
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Hybrid Simulations of a Tangential Discontinuity‐Driven Foreshock Bubble Formation in Comparison With a Hot Flow Anomaly Formation

Journal of Geophysical Research: Space Physics, 2022
AbstractHot flow anomalies (HFAs) and foreshock bubbles (FBs) are significant foreshock transients that can accelerate particles and disturb the magnetosphere‐ionosphere system. Yet, their early formation mechanisms are still not fully understood. To investigate the formation of tangential discontinuity (TD)‐driven FBs and HFAs, we use 2‐D local hybrid
Andrew Vu, Terry Z. Liu, Hui Zhang, Peter Delamere   +3 more
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Ion Acceleration by Foreshock Bubbles: Magnetospheric Multiscale Observations

Journal of Geophysical Research: Space Physics, 2023
AbstractForeshock bubbles (FBs) occur when interplanetary magnetic field discontinuities encounter the Earth's foreshock. These transient (∼1 to 5 min) features exhibit depressed densities and magnetic field strengths, enhanced temperatures, and deflected plasma flows trailed by a region of enhanced plasma density and magnetic field strength.
S. H. Lee, D. G. Sibeck, N. Omidi, M. V. D. Silveira, A. Vu, S. K. Vines, I. J. Cohen, S. A. Fuselier, H. Wei, C. T. Russell, J. L. Burch   +10 more
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