A5053132465- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Stellar, planetary, and galactic studies
- Solar Radiation and Photovoltaics
- Atmospheric Ozone and Climate
- Geophysics and Gravity Measurements
- Calibration and Measurement Techniques
- Spacecraft and Cryogenic Technologies
- Advanced Thermodynamics and Statistical Mechanics
- Adaptive optics and wavefront sensing
- Solar Thermal and Photovoltaic Systems
- Aquatic and Environmental Studies
- Atmospheric and Environmental Gas Dynamics
- Nuclear Physics and Applications
- Metallurgical Processes and Thermodynamics
- Photovoltaic System Optimization Techniques
- Advanced Control Systems Optimization
- Spacecraft Design and Technology
- CCD and CMOS Imaging Sensors
- Space exploration and regulation
- Academic Publishing and Open Access
- Guidance and Control Systems
- Earthquake Detection and Analysis
National Oceanic and Atmospheric Administration
2007-2023
NOAA Space Weather Prediction Center
2011-2017
United States Naval Research Laboratory
1996
K Lab (United States)
1996
VIP Sensors (United States)
1994
NSF National Center for Atmospheric Research
1985-1992
High Altitude Observatory
1972-1986
U.S. National Science Foundation
1986
Goddard Space Flight Center
1979-1980
The Wang‐Sheeley model is an empirical that can predict the background solar wind speed and interplanetary magnetic field (IMF) polarity. We make a number of modifications to basic technique greatly improve performance reliability model. First, we establish continuous function relates expansion factor velocity at source surface. Second, propagate from surface Earth using assumption radial streams simple scheme account for their interactions. Third, develop apply method identifying removing...
The focus of this paper is two‐fold: (1) to examine how the presence spiral magnetic field affects evolution interplanetary corotating solar wind streams, and (2) ascertain nature secondary large‐scale phenomena likely be associated with streams having a pronounced three‐dimensional (3‐D) structure. dynamics are presumed governed by nonlinear, polytropic, single‐fluid, 3‐D MHD equations. Solutions obtained an explicit, Eulerian, finite differences technique that makes use simple form...
Ulysses‧ initial transit to high heliographic latitudes at a heliocentric distance of ∼5 AU has revealed systematic effects in the latitudinal evolution corotating interaction regions (CIRs). At latitude corresponding roughly to, but slightly less than, inferred tilt coronal streamer belt and embedded heliospheric current sheet, strong forward shocks commonly associated with CIRs lower disappeared almost entirely; however, reverse these persisted ∼ 10° above belt. Systematic meridional flow...
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...
We develop a numerical model that treats the three‐dimensional (3‐D) magnetohydrodynamic interactions taking place at interplanetary corotating stream fronts near heliographic equator during those periods of solar cycle when large‐scale coronal magnetic structure is in tilted‐dipole configuration. The dynamic simplicity geometry permits formulation local approximation valid over limited range latitudes and longitudes centered about front. show one component spatial orientation interface...
This paper explores theoretical aspects of corotating solar wind dynamics on a global scale by means numerical simulations executed with nonlinear, inviscid, adiabatic, single‐fluid, three‐dimensional (3‐D) hydrodynamic formulation. The study begins simple hypothetical 3‐D stream structure defined source surface located at 35 R S and carefully documents its evolution to 1 AU under the influence rotation. By manipulating this prototype configuration surface, it is possible elucidate factors...
view Abstract Citations (103) References (48) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Determination of the solar wind angular momentum flux from HELIOS data - an observational test Weber and Davis theory Pizzo, V. ; Schwenn, R. Marsch, E. Rosenbauer, H. Muehlhaeuser, K. -H. Neubauer, F. M. In situ attempts to measure sun's loss in thereby description magnetic coupling between stellar rotation winds have thus far produced widely divergent inconclusive...
Coronal mass ejections (CMEs)—massive explosions of dense plasma that originate in the lower solar atmosphere and propagate outward into wind—are leading cause significant space weather effects within Earth's environment. Computational models heliosphere such as WSA‐Enlil offer possibility predicting whether a given CME will become geo‐effective and, if so, likely time arrival at Earth. To be meaningful, forecast model is dependent upon accurately characterizing key parameters for CME,...
Space weather research requires investigation of a complex chain coupled dynamic phenomena occurring simultaneously on various spatial and temporal scales between the Sun Earth. Specialized physically based numerical models have been developed to address particular aspects entire system. However, an integrated modeling approach is necessary provide complete picture suitable for interpretation remote in situ observations development forecasting capabilities. In this paper we demonstrate...
Since measurements began in the late nineteenth century, there has been a secular increase (with superposed ripples due to solar cycles) of aa geomagnetic index [ Mayaud , 1972 ]. Starting from this observation, Lockwood et al. [1999a 1999b] conclude that total open magnetic flux increased by 41% 1964 1995 and 130% over all but last 5 years twentieth century. However, data for more than two cycles ‐ Carrington maps Mount Wilson, Wilcox Solar Observatories newly reanalyzed National...
Abstract On 23 July 2012 a significant and rapid coronal mass ejection (CME) was detected in situ by the Solar Terrestrial Relations Observatory (STEREO) A. This CME unusual due to its extremely brief Sun‐to‐1 AU transit time of less than 21 h exceptionally high impact speed 2246 km/s. If this had been Earth directed, it would have produced geomagnetic storm with potentially serious consequences. To protect our ground‐ space‐based assets, there is clear need accurately forecast arrival times...
Abstract We analyze the high-energy particle emission from Sun in two extreme solar events which protons are accelerated to relativistic energies and can cause a significant signal even ground-based detectors. Analysis of proton event is based on modeling transport interaction, near-Sun source through wind Earth’s magnetosphere atmosphere detector ground. This allows us deduce time profile at compare it with observed electromagnetic emissions. The 1998 May 2 associated flare coronal mass...
A three‐dimensional (3‐D) magnetohydrodynamic (MHD) numerical model is used to simulate the global evolution of a steady, tilted‐dipole solar wind flow configuration similar that prevalent in interplanetary space 1993. Systematic latitudinal changes structure corotating interaction region (CIR) near 5 AU shown agree well with recent Ulysses observations. The abrupt disappearance forward shocks and continued persistence reverse poleward latitude where crossed southern edge coronal streamer...
view Abstract Citations (98) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Numerical Solution of the Magnetostatic Equations for Thick Flux Tubes, with Application to Sunspots, Pores, and Related Structures Pizzo, V. J. An iterative numerical technique permitting solution, in great generality, nonlinear boundary value problem associated two-dimensional magnetostatic equilibrium, which may be extended any geometry one ignorable coordinate...
Coronal transients are believed to involve the expulsion of magnetic ‘bubbles’ or loops into interplanetary space. The close relationship coronal with other forms solar activity suggests a variation in their frequency occurrence by factor 3–10 over cycle. As ‘inclusions’ field, should then lead cycle dependent scattering cosmic rays entering inner system. power spectrum model transverse fluctuations and its dependence is compared observed spectra. tentatively identified as origin...
The interpretation of multi-spacecraft heliospheric observations and three-dimensional reconstruction structured evolving solar wind is challenging. This especially true for the white-light structures observed by Heliospheric Imagers (HI) onboard STEREO spacecraft since their appearance depends on geometric factors. Numerical simulations can provide global context suggest what may not be observed. We use code ENLIL to simulate various scenarios well-defined corotating streams ejected...
Using a coupled 2.5-dimensional, time-dependent MHD model of the solar corona and inner heliosphere, we have simulated eruption evolution coronal mass ejection containing flux rope all way from Sun to 1 AU. Although idealized, find that simulation reproduces many generic features magnetic clouds. In this paper report on new, intriguing aspect these comparisons. Specifically, results suggest jetted outflow, driven by posteruptive reconnection underneath rope, occurs may remain intact out AU...