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Space Plasma Physicist
  • 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. 

Scholarly Publications

Energetic particle loss through the magnetopause: A combined global MHD and test-particle study

Journal of Geophysical Research-Space Physics, 2017
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

Ion acceleration at dipolarization fronts in the inner magnetosphere

Journal of Geophysical Research-Space Physics, 2017
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

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, 2017
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

Second harmonic poloidal waves observed by Van Allen Probes in the dusk-midnight sector

Journal of Geophysical Research-Space Physics, 2017
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

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, 2016
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

History and Science Motivation for the Van Allen Probes Mission

Johns Hopkins Apl Technical Digest, 2016
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

Reproducing the observed energy-dependent structure of Earth's electron radiation belts during storm recovery with an event-specific diffusion model

Geophysical Research Letters, 2016
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

Storm time dynamics of ring current protons: Implications for the long-term energy budget in the inner magnetosphere

Geophysical Research Letters, 2016
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

The Van Allen Probes' Contribution to the Space Weather System

Johns Hopkins Apl Technical Digest, 2016
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

Van Allen Probes Mission Overview and Discoveries to Date

Johns Hopkins Apl Technical Digest, 2016
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

Global storm time depletion of the outer electron belt

Journal of Geophysical Research-Space Physics, 2015
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

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, 2015
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

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, 2015
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

Enhanced radial transport and energization of radiation belt electrons due to drift orbit bifurcations

Journal of Geophysical Research-Space Physics, 2014
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

Preferential acceleration of heavy ions in the reconnection outflow region Drift and surfatron ion acceleration

Astronomy & Astrophysics, 2014
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

Rotationally driven 'zebra stripes' in Earth's inner radiation belt

Nature, 2014
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-+

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, 2014
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

Acceleration of ions in the Jupiter magnetotail: Particle resonant interaction with dipolarization fronts

Planetary and Space Science, 2013
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

Dynamics of Radiation Belt Particles

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

Global characteristics of electromagnetic ion cyclotron waves: Occurrence rate and its storm dependence

Journal of Geophysical Research-Space Physics, 2013
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

Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE)

Space Science Reviews, 2013
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

Rapid acceleration of protons upstream of earthward propagating dipolarization fronts

Journal of Geophysical Research-Space Physics, 2013
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

Science Objectives and Rationale for the Radiation Belt Storm Probes Mission

Space Science Reviews, 2013
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

Forecasting of global data-binning parameters for high-resolution empirical geomagnetic field models

Space Weather-the International Journal of Research and Applications, 2012
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

Nonlinear Radial Transport in the Earth's Radiation Belts

Dynamics of the Earth's Radiation Belts and Inner Magnetosphere, 2012
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

Radiation belt storm probes: Resolving fundamental physics with practical consequences

Journal of Atmospheric and Solar-Terrestrial Physics, 2011
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

The role of drift orbit bifurcations in energization and loss of electrons in the outer radiation belt

Journal of Geophysical Research-Space Physics, 2011
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

Empirical modeling of a CIR-driven magnetic storm

Journal of Geophysical Research-Space Physics, 2010
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

Rapid scattering of radiation belt electrons by storm-time EMIC waves

Geophysical Research Letters, 2010
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

Spatial distribution of relativistic electron precipitation during a radiation belt depletion event

Geophysical Research Letters, 2010
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

Radial transport of radiation belt electrons due to stormtime Pc5 waves

Annales Geophysicae, 2009
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

Dynamical data-based modeling of the storm-time geomagnetic field with enhanced spatial resolution

Journal of Geophysical Research-Space Physics, 2008
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

Radial transport in the outer radiation belt due to global magnetospheric compressions

Journal of Atmospheric and Solar-Terrestrial Physics, 2008
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

SPECIAL ISSUE Dynamic Variability of Earth's Radiation Belts Preface

Journal of Atmospheric and Solar-Terrestrial Physics, 2008
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

Timing analysis of the relationship between solar wind parameters and geosynchronous Pc5 amplitude

Journal of Geophysical Research-Space Physics, 2008
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

Solar wind control of Pc5 pulsation power at geosynchronous orbit

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

Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons

Geophysical Research Letters, 2006
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

Storm time evolution of the outer radiation belt: Transport and losses

Journal of Geophysical Research-Space Physics, 2006
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

Global and multiscale phenomena of the magnetosphere

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

Impact of toroidal ULF waves on the outer radiation belt electrons

Journal of Geophysical Research-Space Physics, 2005
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

Roles of chaos, self-organized criticality and phase transitions in magnetospheric physics

Multiscale Coupling of Sun-Earth Processes, 2005
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

Storm time dawn-dusk asymmetry of the large-scale Birkeland currents

Journal of Geophysical Research-Space Physics, 2005
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

Data-derived forecasting model for relativistic electron intensity at geosynchronous orbit

Geophysical Research Letters, 2004
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

Global and multi-scale features of solar wind-magnetosphere coupling: From modeling to forecasting

Geophysical Research Letters, 2004
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

Combining global and multi-scale features in a description of the solar wind-magnetosphere coupling

Annales Geophysicae, 2003
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

Global and multiscale aspects of magnetospheric dynamics in local-linear filters

Journal of Geophysical Research-Space Physics, 2002
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

Observations of electromagnetic ion cyclotron waves during geomagnetic storms: Wave occurrence and pitch angle scattering

Journal of Geophysical Research-Space Physics, 2001
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