Sasha Ukhorskiy Print


  240-228-0201

  Aleksandr.Ukhorskiy@jhuapl.edu

: SES

:   Space Plasma Physicist

:  Heliophysics

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Degree Field of Study Year Attained Institution Name
PhD Physics 2003 UMD
MS Physics 1999 MIPT

Publications: Over 35 publications in refereed journals.

Project Scientist of the Van Allen Probes NASA Mission.

Research Interests Include:

  • Energetic particles in space. Transport, acceleration and loss of energetic ions and relativistic electrons in the inner magnetosphere of Earth and outer planets. Theoretical and numerical analysis of radial transport and loss in the outer electron belt. Mechanisms of ion acceleration at ring current injections, plasma bubbles and dipolarization fronts. Global kinetic modeling of the near-Earth radiation environment. Assimilation of in situ spacecraft measurements into kinetic models of Earth’s radiation belts. Dynamical chaos of energetic electron motion in magnetospheric fields. 
  • Magnetospheric plasma waves. Generation and propagation of ULF (Pc3-5), EMIC and whistler waves in Earth’s magnetosphere. Data analysis and statistical studies of ULF and EMIC wave properties in the inner magnetosphere. Numerical modeling of MHD waves in Earth’s magnetosphere. Computation of EMIC and whistler wave growth rates. Theoretical and numerical analysis of cyclotron wave-particle interactions and local acceleration/loss rates of ring current and radiation belt particles.     
  • Nonlinear processes in space plasmas. Data-derived dynamical models of magnetospheric fields and geomagnetic indices. Nonlinear time series analysis: correlation dimension, delay embedding, local-linear filters, multifractal analysis. Magnetospheric phase transitions: mean-field description of substorms, critical exponents, fluctuation analysis. 
 
AGU Index Category AGU Index Sub-Category
MAGNETOSPHERIC PHYSICS Magnetosphere: inner
SPACE PLASMA PHYSICS Nonlinear phenomena
MAGNETOSPHERIC PHYSICS Radiation belts
SPACE PLASMA PHYSICS Wave/particle interactions
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Start Year End Year Description
2006 Current Principal Professional Staff, JHU/APL, Laurel, MD
2015 Current Project Scientist of NASA Van Allen Probes Mission
2010 Current Co-Investigator of the RBSPICE investigation of NASA Van Allen Probes Mission
2012 Current Adjunct Professor, Dartmouth College, Hanover, NH
2007 2015 Instructor of graduate physics course: Plasma Physics, JHU Whiting School of Engineering, Laurel, MD
2003 2006 Postdoctoral Fellow, JHU/APL, Laurel, MD
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The following publication information was downloaded from

ORCID logo https://orcid.org/0000-0002-3326-4024

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K. A. Sorathia, V. G. Merkin, A. Y. Ukhorskiy, B. H. Mauk, D. G. Sibeck, (2017), Energetic particle loss through the magnetopause: A combined global MHD and test-particle study, Journal of Geophysical Research-Space Physics, 122, 9, 9329-9343

A. Y. Ukhorskiy, M. I. Sitnov, V. G. Merkin, M. Gkioulidou, D. G. Mitchell, (2017), Ion acceleration at dipolarization fronts in the inner magnetosphere, Journal of Geophysical Research-Space Physics, 122, 3, 3040-3054

D. L. Turner, J. F. Fennell, J. B. Blake, S. G. Claudepierre, J. H. Clemmons, A. N. Jaynes, T. Leonard, D. N. Baker, I. J. Cohen, M. Gkioulidou, A. Y. Ukhorskiy, B. H. Mauk, C. Gabrielse, V. Angelopoulos, R. J. Strangeway, C. A. Kletzing, O. Le Contel, H. E. Spence, R. B. Torbert, J. L. Burch, G. D. Reeves, (2017), Multipoint Observations of Energetic Particle Injections and Substorm Activity During a Conjunction Between Magnetospheric Multiscale (MMS) and Van Allen Probes, Journal of Geophysical Research-Space Physics, 122, 11, 11481-11504

Kyungguk Min, Kazue Takahashi, Aleksandr Y. Ukhorskiy, JerryW. Manweiler, Harlan E. Spence, Howard J. Singer, Seth G. Claudepierre, Brian A. Larsen, A. Rualdo Soto-Chavez, Ross J. Cohen, (2017), Second harmonic poloidal waves observed by Van Allen Probes in the dusk-midnight sector, Journal of Geophysical Research-Space Physics, 122, 3, 3013-3039

G. K. Stephens, M. I. Sitnov, A. Y. Ukhorskiy, E. C. Roelof, N. A. Tsyganenko, G. Le, (2016), Empirical modeling of the storm time innermost magnetosphere using Van Allen Probes and THEMIS data: Eastward and banana currents, Journal of Geophysical Research-Space Physics, 121, 1, 157-170

Barry H. Mauk, Aleksandr Y. Ukhorskiy, Nicola J. Fox, Ramona L. Kessel, David G. Sibeck, Shrikanth G. Kanekal, (2016), History and Science Motivation for the Van Allen Probes Mission, Johns Hopkins Apl Technical Digest, 33, 3, 165-172

J. -F. Ripoll, G. D. Reeves, G. S. Cunningham, V. Loridan, M. Denton, O. Santolik, W. S. Kurth, C. A. Kletzing, D. L. Turner, M. G. Henderson, A. Y. Ukhorskiy, (2016), Reproducing the observed energy-dependent structure of Earth's electron radiation belts during storm recovery with an event-specific diffusion model, Geophysical Research Letters, 43, 11, 5616-5625

Matina Gkioulidou, A. Y. Ukhorskiy, D. G. Mitchell, L. J. Lanzerotti, (2016), Storm time dynamics of ring current protons: Implications for the long-term energy budget in the inner magnetosphere, Geophysical Research Letters, 43, 10, 4736-4744

Lawrence J. Zanetti, Ramona L. Kessel, Barry H. Mauk, Aleksandr Y. Ukhorskiy, Nicola J. Fox, Robin J. Barnes, Michele Weiss, Thomas S. Sotirelis, NourEddine Raouafi, (2016), The Van Allen Probes' Contribution to the Space Weather System, Johns Hopkins Apl Technical Digest, 33, 3, 194-201

Elena Y. Adams, Kristin A. Fretz, Aleksandr Y. Ukhorskiy, Nicola J. Fox, (2016), Van Allen Probes Mission Overview and Discoveries to Date, Johns Hopkins Apl Technical Digest, 33, 3, 173-182

A. Y. Ukhorskiy, M. I. Sitnov, R. M. Millan, B. T. Kress, J. F. Fennell, S. G. Claudepierre, R. J. Barnes, (2015), Global storm time depletion of the outer electron belt, Journal of Geophysical Research-Space Physics, 120, 4, 2543-2556

T. Motoba, K. Takahashi, A. Ukhorskiy, M. Gkioulidou, D. G. Mitchell, L. J. Lanzerotti, G. I. Korotova, E. F. Donovan, J. R. Wygant, C. A. Kletzing, W. S. Kurth, J. B. Blake, (2015), Link between premidnight second harmonic poloidal waves and auroral undulations: Conjugate observations with a Van Allen Probe spacecraft and a THEMIS all-sky imager, Journal of Geophysical Research-Space Physics, 120, 3, 1814-1831

Matina Gkioulidou, S. Ohtani, D. G. Mitchell, A. Y. Ukhorskiy, G. D. Reeves, D. L. Turner, J. W. Gjerloev, M. Nose, K. Koga, J. V. Rodriguez, L. J. Lanzerotti, (2015), Spatial structure and temporal evolution of energetic particle injections in the inner magnetosphere during the 14 July 2013 substorm event, Journal of Geophysical Research-Space Physics, 120, 3, 1924-1938

A. Y. Ukhorskiy, M. I. Sitnov, R. M. Millan, B. T. Kress, D. C. Smith, (2014), Enhanced radial transport and energization of radiation belt electrons due to drift orbit bifurcations, Journal of Geophysical Research-Space Physics, 119, 1, 163-170

A. V. Artemyev, G. Zimbardo, A. Y. Ukhorskiy, M. Fujimoto, (2014), Preferential acceleration of heavy ions in the reconnection outflow region Drift and surfatron ion acceleration, Astronomy & Astrophysics, 562

A. Y. Ukhorskiy, M. I. Sitnov, D. G. Mitchell, K. Takahashi, L. J. Lanzerotti, B. H. Mauk, (2014), Rotationally driven 'zebra stripes' in Earth's inner radiation belt, Nature, 507, 7492, 338-+

Matina Gkioulidou, A. Y. Ukhorskiy, D. G. Mitchell, T. Sotirelis, B. H. Mauk, L. J. Lanzerotti, (2014), The role of small-scale ion injections in the buildup of Earth's ring current pressure: Van Allen Probes observations of the 17 March 2013 storm, Journal of Geophysical Research-Space Physics, 119, 9

A. V. Artemyev, S. Kasahara, A. Y. Ukhorskiy, M. Fujimoto, (2013), Acceleration of ions in the Jupiter magnetotail: Particle resonant interaction with dipolarization fronts, Planetary and Space Science, 82-83, 134-148

A. Y. Ukhorskiy, M. I. Sitnov, (2013), Dynamics of Radiation Belt Particles, Space Science Reviews, 179, 1-4, 545-578

Kunihiro Keika, Kazue Takahashi, Aleksandir Y. Ukhorskiy, Yoshizumi Miyoshi, (2013), Global characteristics of electromagnetic ion cyclotron waves: Occurrence rate and its storm dependence, Journal of Geophysical Research-Space Physics, 118, 7, 4135-4150

D. G. Mitchell, L. J. Lanzerotti, C. K. Kim, M. Stokes, G. Ho, S. Cooper, A. Ukhorskiy, J. W. Manweiler, S. Jaskulek, D. K. Haggerty, P. Brandt, M. Sitnov, K. Keika, J. R. Hayes, L. E. Brown, R. S. Gurnee, J. C. Hutcheson, K. S. Nelson, N. Paschalidis, E. Rossano, S. Kerem, (2013), Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE), Space Science Reviews, 179, 1-4, 263-308

A. Y. Ukhorskiy, M. I. Sitnov, V. G. Merkin, A. V. Artemyev, (2013), Rapid acceleration of protons upstream of earthward propagating dipolarization fronts, Journal of Geophysical Research-Space Physics, 118, 8, 4952-4962

B. H. Mauk, N. J. Fox, S. G. Kanekal, R. L. Kessel, D. G. Sibeck, A. Ukhorskiy, (2013), Science Objectives and Rationale for the Radiation Belt Storm Probes Mission, Space Science Reviews, 179, 1-4, 3-27

M. I. Sitnov, A. Y. Ukhorskiy, G. K. Stephens, (2012), Forecasting of global data-binning parameters for high-resolution empirical geomagnetic field models, Space Weather-the International Journal of Research and Applications, 10

B. T. Kress, M. K. Hudson, A. Y. Ukhorskiy, H. -R. Mueller, D Summers, IR Mann, DN Baker, M Schulz, (2012), Nonlinear Radial Transport in the Earth's Radiation Belts, Dynamics of the Earth's Radiation Belts and Inner Magnetosphere, 199, 151-160

Aleksandr Y. Ukhorskiy, Barry H. Mauk, Nicola J. Fox, David G. Sibeck, Joseph M. Grebowsky, (2011), Radiation belt storm probes: Resolving fundamental physics with practical consequences, Journal of Atmospheric and Solar-Terrestrial Physics, 73, 11-12, 1417-1424

A. Y. Ukhorskiy, M. I. Sitnov, R. M. Millan, B. T. Kress, (2011), The role of drift orbit bifurcations in energization and loss of electrons in the outer radiation belt, Journal of Geophysical Research-Space Physics, 116

M. I. Sitnov, N. A. Tsyganenko, A. Y. Ukhorskiy, B. J. Anderson, H. Korth, A. T. Y. Lui, P. C. Brandt, (2010), Empirical modeling of a CIR-driven magnetic storm, Journal of Geophysical Research-Space Physics, 115

A. Y. Ukhorskiy, Y. Y. Shprits, B. J. Anderson, K. Takahashi, R. M. Thorne, (2010), Rapid scattering of radiation belt electrons by storm-time EMIC waves, Geophysical Research Letters, 37

R. M. Millan, K. B. Yando, J. C. Green, A. Y. Ukhorskiy, (2010), Spatial distribution of relativistic electron precipitation during a radiation belt depletion event, Geophysical Research Letters, 37

A. Y. Ukhorskiy, M. I. Sitnov, K. Takahashi, B. J. Anderson, (2009), Radial transport of radiation belt electrons due to stormtime Pc5 waves, Annales Geophysicae, 27, 5, 2173-2181

M. I. Sitnov, N. A. Tsyganenko, A. Y. Ukhorskiy, P. C. Brandt, (2008), Dynamical data-based modeling of the storm-time geomagnetic field with enhanced spatial resolution, Journal of Geophysical Research-Space Physics, 113, A7

Aleksandr Y. Ukhorskiy, Mikhail I. Sitnov, (2008), Radial transport in the outer radiation belt due to global magnetospheric compressions, Journal of Atmospheric and Solar-Terrestrial Physics, 70, 14, 1714-1726

A. Y. Ukhorskiy, T. P. O'Brien, D. G. Sibeck, (2008), SPECIAL ISSUE Dynamic Variability of Earth's Radiation Belts Preface, Journal of Atmospheric and Solar-Terrestrial Physics, 70, 14, V

Kazue Takahashi, Aleksandr Y. Ukhorskiy, (2008), Timing analysis of the relationship between solar wind parameters and geosynchronous Pc5 amplitude, Journal of Geophysical Research-Space Physics, 113, A12

Kazue Takahashi, Aleksandr Y. Ukhorskiy, (2007), Solar wind control of Pc5 pulsation power at geosynchronous orbit, Journal of Geophysical Research-Space Physics, 112, A11

AY Ukhorskiy, BJ Anderson, K Takahashi, NA Tsyganenko, (2006), Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons, Geophysical Research Letters, 33, 6

A. Y. Ukhorskiy, B. J. Anderson, P. C. Brandt, N. A. Tsyganenko, (2006), Storm time evolution of the outer radiation belt: Transport and losses, Journal of Geophysical Research-Space Physics, 111, A11

AS Sharma, AY Ukhorskiy, MI Sitnov, PK Kaw, (2005), Global and multiscale phenomena of the magnetosphere, Nonequilibrium Phenomena in Plasmas, 321 , 117-143

AY Ukhorskiy, K Takahashi, BJ Anderson, H Korth, (2005), Impact of toroidal ULF waves on the outer radiation belt electrons, Journal of Geophysical Research-Space Physics, 110, A10

MI Sitnov, AY Ukhorskiy, AS Sharma, RS Weigel, ATY Lui, Y Kamide, G Consolini, (2005), Roles of chaos, self-organized criticality and phase transitions in magnetospheric physics, Multiscale Coupling of Sun-Earth Processes, 195-215

BJ Anderson, SI Ohtani, H Korth, A Ukhorskiy, (2005), Storm time dawn-dusk asymmetry of the large-scale Birkeland currents, Journal of Geophysical Research-Space Physics, 110, A12

AY Ukhorskiy, MI Sitnov, AS Sharma, BJ Anderson, S Ohtani, ATY Lui, (2004), Data-derived forecasting model for relativistic electron intensity at geosynchronous orbit, Geophysical Research Letters, 31, 9

AY Ukhorskiy, MI Sitnov, AS Sharma, K Papadopoulos, (2004), Global and multi-scale features of solar wind-magnetosphere coupling: From modeling to forecasting, Geophysical Research Letters, 31, 8

AY Ukhorskiy, MI Sitnov, AS Sharma, K Papadopoulos, (2003), Combining global and multi-scale features in a description of the solar wind-magnetosphere coupling, Annales Geophysicae, 21, 9, 1913-1929

AY Ukhorskiy, MI Sitnov, AS Sharma, K Papadopoulos, (2002), Global and multiscale aspects of magnetospheric dynamics in local-linear filters, Journal of Geophysical Research-Space Physics, 107, A11

RE Erlandson, AJ Ukhorskiy, (2001), Observations of electromagnetic ion cyclotron waves during geomagnetic storms: Wave occurrence and pitch angle scattering, Journal of Geophysical Research-Space Physics, 106, A3, 3883-3895