A5058025120- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- Meteorological Phenomena and Simulations
- Spacecraft Design and Technology
- Industrial Vision Systems and Defect Detection
- Magnetic confinement fusion research
- Planetary Science and Exploration
- GNSS positioning and interference
- Atmospheric Ozone and Climate
- Space exploration and regulation
- Space Science and Extraterrestrial Life
- Advanced Surface Polishing Techniques
- Magnetic Field Sensors Techniques
- Robotics and Sensor-Based Localization
- 3D Surveying and Cultural Heritage
- Geological and Geochemical Analysis
- Optical measurement and interference techniques
- Atmospheric and Environmental Gas Dynamics
- Inertial Sensor and Navigation
- Diabetes Management and Research
- Surface Roughness and Optical Measurements
Virginia Tech
2015-2024
National Institute of Aerospace
2013-2023
Data:Lab Munich (Germany)
2023
Volkswagen Group (Germany)
2023
University of New Hampshire
2023
University of New Hampshire at Manchester
2023
University of Bremen
2012-2016
Bremer Institut für Produktion und Logistik GmbH
2013-2016
Technion – Israel Institute of Technology
2016
Hampton Roads Sanitation District
2012
The nature of manufacturing systems faces ever more complex, dynamic and at times even chaotic behaviors. In order to being able satisfy the demand for high-quality products in an efficient manner, it is essential utilize all means available. One area, which saw fast pace developments terms not only promising results but also usability, machine learning. Promising answer many old new challenges manufacturing, learning widely discussed by researchers practitioners alike. However, field very...
Improved techniques have been developed for empirical modeling of the high‐latitude electric potentials and magnetic field‐aligned currents (FAC) as a function solar wind parameters. The FAC model is constructed using scalar Euler functions twin to potential model. improved models more accurate field values plus boundary locations. Nonlinear saturation effects in wind–magnetosphere coupling are also better reproduced. hybrid technique, which has spherical harmonic only within small area at...
New models of the high‐latitude electric potentials have been developed. These show how polar ionospheric field, or plasma convection, responds to changes in interplanetary magnetic field (IMF) and other parameters, such as dipole tilt angle. patterns were derived from measurements on DE 2 satellite, using all cap passes during which high‐resolution IMF data available ISEE 3 IMP 8 satellites. The are sorted according angle GSM Y‐Z plane. further divided into different groups magnitude All...
An improved model of ionospheric electric potentials/convection patterns is presented here. This will produce potentials for any desired level interplanetary magnetic field (IMF), solar wind velocity, number density, and dipole tilt angle, as well an optional value the AL index. The following improvements have been made: (1) Terms dynamics pressure added. (2) Nonlinear changes in magnitude IMF increases, owing to decreasing effective width coupling region, are now allowed. (3) lower boundary...
A method has been developed to derive the electric potentials in high‐latitude ionosphere resulting from any arbitrary combination of interplanetary magnetic field (IMF) magnitude and orientation, solar wind velocity, dipole tilt angle. This model is based on spherical harmonic coefficients that were derived by a least error fit measurements multiple satellite passes. These have found systematic variations can be reproduced Fourier series linear regression formula. Examples output are shown....
The theta aurora is a remarkable configuration of auroral and polar cap luminosities for which generally sun‐aligned transpolar arc extends contiguously from the dayside to nightside sectors oval. Four individual occurrences over earth's northern hemisphere are examined in detail with global imaging instrumentation on board high‐altitude, polar‐orbiting spacecraft DE 1. Simultaneous measurements fields plasmas this high‐altitude its low‐altitude, companion, 2, order establish an overview...
It has been known that the fluctuations in interplanetary magnetic field (IMF) may be oriented approximately planar structures are tilted with respect to solar wind propagation direction along Sun‐Earth line. This tilting causes IMF propagating from a point of measurement arrive at other locations timing significantly different what would expected. The differences between expected and actual arrival times exceed an hour, tilt angles subsequent delays have substantial changes just few...
We present a comparison between simple but general model of solar wind‐magnetosphere‐ionosphere coupling (the Hill model) and the output global magnetospheric MHD code, Integrated Space Weather Prediction Model (ISM). The predicts transpolar potential region 1 currents from environmental conditions specified at both boundaries magnetosphere: wind boundary, electric field strength, ram pressure, interplanetary magnetic direction; ionospheric conductance dipole strength. As its defining...
Plasma, magnetic‐field and dc electric‐field observations from Dynamics Explorers 1 2 are used to investigate the morphology of solar‐wind ion injection, Birkeland currents, plasma convection in morning sector for both positive negative interplanetary magnetic field (IMF) B y components. The results study construct a ‐dependent global model southward IMF. A significant element is coexistence three types cells (“merging cells,” “viscous “lobe cells”). This can account nearly stationary (in...
A new technique for mapping field‐aligned currents (FAC) with satellite magnetometer data has been used Dynamics Explorer 2 measurements to produce an empirical model which maps the above high‐latitude ionosphere as a function of interplanetary magnetic field (IMF), solar wind velocity, density, and dipole tilt angle. This uses scalar Euler potentials, derived from integrating measured deviations in much same way electric potentials are fields. method works any configuration two‐dimensional...
Nearly simultaneous measurements of auroral zone electric fields are obtained by the Dynamics Explorer spacecraft at altitudes below 900 km and above 4500 during magnetic conjunctions. The measured usually nearly perpendicular to field lines. north‐south meridional “projected” a common altitude mapping function which accounts for convergence When plotted as invariant latitude, graphs projected both DE 1 2 show that large‐scale is same altitudes, expected. Superimposed on fields, however,...
In this paper we continue the community‐wide rigorous modern space weather model validation efforts carried out within GEM, CEDAR and SHINE programs. particular effort, in coordination among Community Coordinated Modeling Center (CCMC), NOAA Space Weather Prediction (SWPC), modelers, science community, focus on studying models' capability to reproduce observed ground magnetic field fluctuations, which are closely related geomagnetically induced current phenomenon. One of primary motivations...
The habitability of the surface any planet is determined by a complex evolution its interior, surface, and atmosphere. electromagnetic particle radiation stars drive thermal, chemical physical alteration planetary atmospheres, including escape. Many known extrasolar planets experience vastly different stellar environments than those in our Solar system: it crucial to understand broad range processes that lead atmospheric escape under wide conditions if we are assess worlds around other...
A technique is described for predicting ground surface geomagnetic variations from measurements of the approaching interplanetary magnetic field (IMF) and solar wind. The method uses twin, empirical representations ionospheric electric Euler potentials' response to IMF drivers. potential model, originally derived mapping large‐scale field‐aligned current structure, describes curl‐free component horizontal current, also called “potential current.” Using approximations that Hall Pedersen...
The current‐voltage relation within narrow auroral current sheets is examined through the use of high‐resolution data from high‐altitude Dynamics Explorer 1 satellite. north‐south perpendicular electric field and east‐west magnetic are shown for three cases in which there large amplitude, oppositely directed paired fields confined to a region less than 20 km wide. variations found be proportional second integral field. It that at small‐scale limit, this relationship between Δ B E consistent...
It has been known that the variations in interplanetary magnetic field (IMF) occur within surfaces are tilted with respect to solar wind velocity vector. This tilting of IMF phase fronts may cause propagation from a point observation another location have delay times vary substantially. Therefore for accurate calculations real time, or creation scientific data sets, it is necessary be able determine surface orientation angles using measurements on one spacecraft only. Methods calculating...
Acquiring quantitative metrics‐based knowledge about the performance of various space physics modeling approaches is central for weather community. Quantification helps users products to better understand capabilities models and choose approach that best suits their specific needs. Further, analyses are important addressing differences between measuring guiding progress in field. In this paper, results ground magnetic field perturbation part Geospace Environment Modeling 2008–2009 Challenge...
In an effort to quantitatively assess the current capabilities of Ionosphere/Thermosphere (IT) models, IT model validation study using metrics was performed. This is a main part CEDAR Electrodynamics Thermosphere Ionosphere (ETI) Challenge, which initiated at workshop in 2009 better comprehend strengths and weaknesses models predicting system, trace improvements ionospheric/thermospheric specification forecast. For challenge, two strong geomagnetic storms, four moderate three quiet time...
Simultaneous measurements of the interplanetary magnetic field (IMF) are obtained at various locations with four spacecraft, ACE, Wind, IMP‐8, and Geotail. We have devised a technique whereby exact propagation delay time between L1 orbit, each other three spacecraft can be derived from these measurements. This is determined as continuously varying function time; when this measured applied to all components IMF by they will match satellites' degree that much better than expected. However,...
As revealed in MHD simulation, the magnetospheric sash is a band of weak magnetic field that, for usual case which IMF approximately perpendicular to geomagnetic dipole, runs tailward along high‐latitude magnetopause flanks from one dayside cusp other, closing via cross‐tail neutral sheet. On flanks, it contains separator line, at all three topological types lines meet. Seen cross‐sectional plane through near‐Earth tail, takes form S, weak‐field feature comprised tail sheet with diagonally...
[1] In the paper “Predicting interplanetary magnetic field (IMF) propagation delay times using minimum variance technique” by D. R. Weimer et al. (Journal of Geophysical Research, 108(A1), 1026, doi:10.1029/2002JA009405, 2003) results shown were obtained a method which was not exactly identical to analysis (MVA) technique. Owing serendipitous error in computer coding, that used actually worked better than MVA would have for this particular application. [4] This problem discovered both T....
We have used output from the Weimer Joule heating model (2005) and Air Force High Accuracy Satellite Drag Model (HASDM) to study response of thermosphere heating. Our period 15 January 29 June 2001 contains a number large small magnetic storms during which thermospheric events occurred. find that new (Weimer, 2005), combined with energy input provided by precipitating particles (NOAA/TIROS hemispheric power index), can supply more than enough account for change in total internal...