A5088604561- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Geomagnetism and Paleomagnetism Studies
- Planetary Science and Exploration
- Stellar, planetary, and galactic studies
- Solar Radiation and Photovoltaics
- Space exploration and regulation
- Earthquake Detection and Analysis
- Spacecraft Design and Technology
- Atmospheric Ozone and Climate
- Global Energy and Sustainability Research
- Space Satellite Systems and Control
- Gas Dynamics and Kinetic Theory
- Space Science and Extraterrestrial Life
- Spacecraft and Cryogenic Technologies
- Meteorological Phenomena and Simulations
- GNSS positioning and interference
- Magnetic confinement fusion research
- Distributed and Parallel Computing Systems
- Scientific Computing and Data Management
- Geological and Geophysical Studies
- earthquake and tectonic studies
- Fluid Dynamics and Turbulent Flows
George Mason University
2015-2024
Goddard Space Flight Center
2012-2023
Heliophysics
2011-2021
Heliophysics Science Division
2020
Cooperative Institute for Research in Environmental Sciences
2003-2016
University of Graz
2015
Space Environment Technologies (United States)
2013
Czech Academy of Sciences, Astronomical Institute
1996-2011
National Oceanic and Atmospheric Administration
1999-2009
University of Colorado Boulder
1999-2009
Numerical three‐dimensional magnetohydrodynamic models are capable of predicting large‐scale solar wind structures at Earth, provided that appropriate time‐dependent boundary conditions specified near the Sun. Since knowledge such is present insufficient to directly drive models, various approximations used. In this paper, we introduce main features and a numerical model where (1) ambient derived from coronal utilizing photospheric magnetic field observations (2) transient disturbances...
A three‐dimensional (3‐D) numerical hydrodynamic model is used to investigate the temporal and spatial evolution of large‐scale solar wind structures. tilted‐dipole outflow configuration specified at inner boundary near Sun, a structured, corotating (SW) flow established by dynamic relaxation. Time‐dependent variation pressure velocity applied generate transient structures within streamer belt. The dynamical interaction coronal mass ejection (CME) with belt between 0.14 5.04 AU then...
We study the interaction of two successive coronal mass ejections (CMEs) during 2010 August 1 events using STEREO/SECCHI COR and HI data. obtain direction motion for both CMEs by applying several independent reconstruction methods find that head in similar directions. This provides evidence a full takes place between can be observed HI1 field-of-view. The de-projected kinematics faster CME from Sun to Earth is derived combining remote observations with situ measurements at AU. speed profile...
The ESA-JAXA BepiColombo mission will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric dynamics at Mercury as well their interactions with the solar wind, radiation, interplanetary dust. Many scientific instruments onboard spacecraft be completely, or partially devoted study near-space environment of complex processes that govern it. issues remain unsolved even after MESSENGER ended in 2015. specific...
http://www.agu.org/journals/sw/swa/news/article/?id=2011SW000669 The National Weather Service's (NWS) Space Prediction Center (SWPC) is transitioning the first large-scale, physics-based space weather prediction model into operations on NWS Centers for Environmental (NCEP) supercomputing system (see also C. Schultz, moves prime time, Weather, 9, S03005, doi:10.1029/2011SW000669, 2011). intended to provide 1- 4-day advance warning of geomagnetic storms from quasi-recurrent solar wind...
Abstract We discuss observations of the journey throughout Solar System a large interplanetary coronal mass ejection (ICME) that was ejected at Sun on 14 October 2014. The ICME hit Mars 17 October, as observed by Express, Atmosphere and Volatile EvolutioN Mission (MAVEN), Odyssey, Science Laboratory (MSL) missions, 44 h before encounter planet with Siding‐Spring comet, for which space weather context is provided. It reached comet 67P/Churyumov‐Gerasimenko, perfectly aligned 3.1 AU, Rosetta...
The successive coronal mass ejections (CMEs) from 2010 July 30 - August 1 present us the first opportunity to study CME-CME interactions with unprecedented heliospheric imaging and in situ observations multiple vantage points. We describe two cases of CME interactions: merging CMEs launched close time overtaking a preceding by shock wave. on interact Sun form merged front, which then overtakes near AU, as revealed wide-angle observations. Connections between signatures at AU suggest that...
Multiple coronal and heliospheric models have been recently upgraded at the Community Coordinated Modeling Center (CCMC), including Wang-Sheeley-Arge (WSA)-Enlil model, MHD-Around-a-Sphere (MAS)-Enlil Space Weather Framework (SWMF), tomography using interplanetary scintillation data. To investigate effects of photospheric magnetograms from different sources, models, model versions on performance, we run these in 10 combinations. Choosing seven Carrington rotations 2007 as time window,...
The Wang-Sheeley-Arge (WSA)−ENLIL+Cone model is used extensively in space weather operations world-wide to coronal mass ejection (CME) propagation. As such, it important assess its performance. We present validation results of the WSA−ENLIL+Cone installed at Community Coordinated Modeling Center (CCMC) and executed real-time by CCMC team. uses predict CME arrivals NASA missions throughout inner heliosphere. In this work we compare predicted arrival-times situ interplanetary leading edge...
Abstract The dual spacecraft mission BepiColombo is the first joint between European Space Agency (ESA) and Japanese Aerospace Exploration (JAXA) to explore planet Mercury. was launched from Kourou (French Guiana) on October 20th, 2018, in its packed configuration including two spacecraft, a transfer module, sunshield. cruise trajectory long journey into inner heliosphere, it includes one flyby of Earth (in April 2020), Venus 2020 August 2021), six Mercury (starting before orbit insertion...
A three‐dimensional (3‐D) numerical hydrodynamic model is used to investigate the evolution of coronal mass ejections (CMEs) launched at several heliographic positions into a tilted‐dipole ambient solar wind (SW) flow, which appropriate around activity minimum and declining phase. The CME injected as an overpressured plasma cloud. Results show that motion local appearance in interplanetary space strongly affected by its interaction with background SW velocity density structures. most...
A three‐dimensional (3‐D) numerical magnetohydrodynamic model is used to investigate the temporal and spatial evolution of large‐scale solar wind (SW) disturbances. tilted dipole outflow configuration specified at inner boundary near Sun, a structured, corotating SW flow with monopolar interplanetary magnetic field (IMF) established by dynamic relaxation between 0.14 1.04 AU. Time‐dependent variation pressure velocity applied simulate injection coronal mass ejection (CME) streamer belt. In...
Time dependent magnetohydrodynamic computations of the flux cancellation mechanism are presented. Previous authors have discussed this as a possible cause for formation prominences and trigger prominence eruptions coronal mass ejections (CMEs). This paper shows that in an energized two-and-one-half-dimensional helmet streamer configuration first leads to stable rope structures. When critical threshold reduction is exceeded, erupts violently. Significant amounts stored magnetic energy...
Recently, we simulated the 12 May 1997 coronal mass ejection (CME) event with a numerical three‐dimensional magnetohydrodynamic model (Odstrcil et al., 2004), in which background solar wind was determined from Science Applications International Corporation (SAIC) (Riley 2001) and transient disturbance cone (Zhao 2002). Although reproduced some fidelity arrival of shock interplanetary CME at Earth, detailed analysis simulations showed poorly defined discrepancies standoff distance between...
Space weather effects on technological systems originate with energy carried from the Sun to terrestrial environment by solar wind. In this study, we present results of modeling corona‐heliosphere processes predict wind conditions at L1 Lagrangian point upstream Earth. particular calculate performance metrics for (1) empirical, (2) hybrid empirical/physics‐based, and (3) full physics‐based coupled models over an 8‐year period (1995–2002). measurements radial speed are primary basis...
We study three CME/ICME events (2008 June 1-6, 2009 February 13-18, 2010 April 3-5) tracked from Sun to 1 AU in remote-sensing observations of STEREO Heliospheric Imagers and situ plasma magnetic field measurements. focus on the ICME propagation IP space that is governed by two forces, propelling Lorentz force drag force. address question at which heliospheric distance range becomes dominant CME gets adjusted solar wind flow. To this aim we analyze speed differences between ICMEs ambient...
Because the material that constitutes a coronal mass ejection expands as it propagates into interplanetary space (where is referred to an ejection, ICME), its sheath differs from other heliophysical sheaths in three ways: (1) lateral deflection of solar wind away nose ICME reduced; (2) tends pile up front instead flowing around it; and (3) thinner. (We refer here have preceding bow shock therefore are analogous sheaths.) These differences explained by physical arguments illustrated with MHD...
Real-time forecasting of the arrival coronal mass ejections (CMEs) at Earth, based on remote solar observations, is one central issues space-weather research. In this paper, we compare arrival-time predictions calculated applying numerical "WSA-ENLIL+Cone model" and analytical "drag-based (DBM). Both models use coronagraphic observations CMEs as input data, thus providing an early forecast two to four days before disturbance depending CME speed. It shown that both methods give very similar...
We present multi-point in situ observations of a complex sequence coronal mass ejections (CMEs) which may serve as benchmark event for numerical and empirical space weather prediction models. On 2010 August 1, instruments on various missions, Solar Dynamics Observatory/Solar Heliospheric Observatory/Solar-TErrestrial-RElations-Observatory (SDO/SOHO/STEREO), monitored several CMEs originating within tens degrees from the solar disk center. compare their imprints four widely separated...