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Emil Lawrence Kepko

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Emil Lawrence Kepko

  • RESEARCH AST, FIELDS AND PARTICLES
  • 301.286.2728
  • NASA/GSFC
  • Mail Code: 675
  • Greenbelt , MD 20771
  • Employer: NASA

    • Brief Bio

    While at NASA/GSFC, I have been fortunate to work on a number of different projects with a variety of roles. My current science interests are focused on understanding pre-onset auroral signatures during magnetospheric substorms, and understanding the source of periodic density structures in the solar wind. In addition to my science interests, I have worked with AETD to develop capabilities on Center to enable highly reliable, highly capable cubesats that can be used either as inexpensive science platforms or could be used to create constellations of satellites. I have been involved in a number of LCAS and OCT proposals, and was Co-I on the ASTRE Heliophysics Explorer, which was selected for Phase A study, losing to eventual winner ICON (PI Tom Immel). I serve on both the Heliophysics and Cross-Cutting Technologies Lines of Business. Finally, I volunteer extensively for community service, including co-chairing the 2012/13 Heliophysics Roadmap, being Editor of JGR - Space Physics (through 2017), and serving on numerous review panels.

    Prior to coming to Goddard, I was worked at both UNH and Boston University. I received my Ph.D. in Geophysics and Space Physics from UCLA, with a thesis entitled, "Transient Convection in the Earth's Magnetosphere and the Generation of Pi2 Pulsations" (Advisor Margaret Kivelson). I was awarded the AGU Fred L. Scarf award, given annually to a recent Ph.D. recipient for outstanding dissertation research that contributes directly to solar-planetary science, in 2002.

    Research Interests

    Small satellites

    Working with both the Heliophysics Science Division (HSD) and the Applied Engineering Technology Directorate (AETD) I continue to push for high reliability and highly capable cubesats and small sats (<30 kg) that can be used to realize NASA's science objectives at a fraction of the cost of larger missions. Advancements in small satellite technologies will further enable constellations of 30+ spacecraft.

    Magnetospheric substorms

    Magnetospheric substorms are a fundamental process by which the magnetosphere processes energy it receives from the solar wind. I study many different aspects of substorms, ranging from Pi2 pulstions (T = 40-150s) that occur impulsively during substorms, to the cause of auroral signatures.

    Solar wind periodic density structures

    Surprisingly, the solar wind appears to contain highly periodic density structures, which in turn drive highly periodic magnetospheric pulsations. The source of these structures hs not been determined, but likely relate back to processes occurring near the solar surface.

    Positions/Employment

    2009 - Present

    Research Astrophysicist

    NASA Goddard Space Flight Center, Greenbelt, MD  
    2007 - 2009

    Research Scientist III

    University of New Hampshire Space Science Center, Durham, NH  
    2004 - 2007

    Senior Research Associate

    Boston University Center for Space Physics, Boston, MA  
    2001 - 2004

    Research Associate

    Boston University Center for Space Physics, Boston, MA  
    2004 - 2007

    Adjunct Professor

    Boston College Department of Geology and Geophysics, Chestnut Hill, MA Taught GE.150, "Introductory Astonomy" each fall semester while continuing full-time research at Boston University

    Education

     Ph.D. in Geophysics and Space Physics, University of California, Los Angeles, 2001
    "Transient convection in the Earth's magnetosphere and the generation of Pi2 pulsations"

    M.S. in Geophysics and Space Physics, University of California, Los Angeles, 1996

    B.S. in Astrophysics, University of California, Los Angeles, 1993

    Professional Service

    NASA
         Co-Chair of the 2012/2013 Heliophysics Roadmap
        Chair of the Geospace MOWG

    American Geophysical Union (AGU)
         Current Editor of JGR - Space Physics

    Goddard Space Flight Center
         Member of the GSFC Scientific Colloquium Committee
        Member of the Science Director's Council
        Member of the GSFC 2030 Science Vision Team

    Conferences and Workshops
         Currently serving 4-year term as lead organizer of IAGA Division.III, "Magnetospheric Phenomena"
        Current active member of the Geospace Environment Modeling (GEM) steering committee
        Co-organizer of the "Modes of magnetospheric response" focus group (completed 5 year term in 2013)
        IAGA 2011/2013/2015 Division III.2 Lead Convener (Magnetospheric substorms and tail physics)
        Program committee, Chapman Conference on "Fundamental Properties and Processes of Magnetotails"
        Program Committee, International Conference on Substorms -7 and -10
        Co-Convener, "Why does geomagentic activity vary with solar cycle?", special session at the 2011 AGU Fall meeting
        Co-Convener, "Modes of magnetospheric transport", special session at the 2008 Fall AGU meeting
        Co-Convener, "ST13: The relationship between global ULF wave modes, plasma gradients and auroral acceleration processes", 2003 joing AGU-EGS meeting.

    Other
        External committee member for Ph.D student Matthew Gilson, University of New Hampshire (Joachim Raeder, advisor). Thesis entitled, “Global structure of the nightside proton precipitation during substorms using simulations and observations.” Defended November, 2011.
        External committee member for Ph.D. student Emma Spanswick, University of Calgary (Eric Donovan, advisor). Thesis entitled, “Global Evolution of Substorm Electron Injections.” Defended January, 2009.


        

    Publications

    Refereed

    Di Matteo, S., U. Villante, N. Viall, L. Kepko, and S. Wallace. 2022. "On Differentiating Multiple Types of ULF Magnetospheric Waves in Response to Solar Wind Periodic Density Structures." Journal of Geophysical Research: Space Physics, 127 (3): [10.1029/2021ja030144]

    Di Matteo, S., N. M. Viall, and L. Kepko. 2021. "Power Spectral Density Background Estimate and Signal Detection via the Multitaper Method." Journal of Geophysical Research: Space Physics, 126 (2): e2020JA028748 [10.1029/2020ja028748]

    Kepko, L., and N. M. Viall. 2019. "The Source, Significance, and Magnetospheric Impact of Periodic Density Structures Within Stream Interaction Regions." Journal of Geophysical Research: Space Physics, (In Press) [10.1029/2019ja026962]

    Di Matteo, S., N. M. Viall, L. Kepko, et al. S. Wallace, C. N. Arge, and P. MacNeice. 2019. "Helios Observations of Quasiperiodic Density Structures in the Slow Solar Wind at 0.3, 0.4, and 0.6 AU." Journal of Geophysical Research: Space Physics, 124 (2): 837-860 [10.1029/2018ja026182]

    Kepko, L., N. Viall, S. K. Antiochos, et al. S. T. Lepri, J. C. Kasper, and M. Weberg. 2016. "Implications of L1 observations for slow solar wind formation by solar reconnection." Geophysical Research Letters, 43 (9): 4089–4097 [10.1002/2016gl068607]

    Le, G., H. Lühr, B. J. Anderson, et al. R. J. Strangeway, C. T. Russell, H. Singer, J. A. Slavin, Y. Zhang, T. Huang, K. Bromund, P. J. Chi, G. Lu, D. Fischer, E. L. Kepko, H. K. Leinweber, W. Magnes, R. Nakamura, F. Plaschke, J. Park, J. Rauberg, C. Stolle, and R. B. Torbert. 2016. "Magnetopause erosion during the March 17, 2015, magnetic storm: Combined field-aligned currents, auroral oval, and magnetopause observations." Geophysical Research Letters, 43 (6): 2396–2404 [10.1002/2016gl068257]

    Kissinger, J., L. Kepko, D. N. Baker, et al. S. Kanekal, W. Li, R. L. McPherron, and V. Angelopoulos. 2014. "The importance of storm time steady magnetospheric convection in determining the final relativistic electron flux level." JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 119: [10.1002/2014JA019948]

    Kepko, E. L., J. Slavin, K.-H. Glassmeier, and T. Sundberg. 2014. "The substorm current wedge at Earth and Mercury." AGU Monograph, "Magnetotails in the Solar System",

    Simoes, F., R. F. Pfaff, H. T. Freudenreich, et al. J. H. Klenzing, D. E. Rowland, K. Bromund, E. L. Kepko, G. Le, M. C. Liebrecht, S. C. Martin, and P. Uribe. 2013. "Equatorial ionosphere semiannual oscillation investigated from Schumann resonance measurements on board the C/NOFS satellite." Journal of Geophysical Research (Atmospheres), 118: 12,045-12,051 [10.1002/jgrd.50797]

    Moore, T. E., M. O. Chandler, N. Buzulukova, et al. G. A. Collinson, E. L. Kepko, K. S. Garcia-Sage, M. G. Henderson, and M. I. Sitnov. 2013. "Snowplow - injection front effects." JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 118: 6478-6488 [10.1002/jgra.50573]

    Moore, T. E., M. O. Chandler, N. Buzulukova, et al. G. A. Collinson, E. L. Kepko, K. S. Garcia-Sage, M. G. Henderson, and M. I. Sitnov. 2013. "'Snowplow' injection front effects." Journal of Geophysical Research (Space Physics), 118: 6478-6488 [10.1002/jgra.50573]

    Kissinger, J., F. Wilder, R. L. McPherron, et al. T. S. Hsu, J. Bake, and E. L. Kepko. 2013. "Statistical occurrence and dynamics of the Harang discontinuity during steady magnetospheric convection." J. Geophys. Res., [10.1002/jgra.50503]

    Gilson, M. L., J. Raeder, E. Donovan, Y. S. Ge, and L. Kepko. 2012. "Global simulation of proton precipitation due to field line curvature during substorms." Journal of Geophysical Research (Space Physics), 117: [5216-10.1029/2012JA017562]

    Keiling, A., K. Shiokawa, V. Uritsky, et al. V. Sergeev, E. Zesta, E. L. Kepko, and N. Østgaard. 2012. "Auroral Signatures of the Dynamic Plasma Sheet, in Auroral Signatures of the Dynamic Plasma Sheet." AGU Monograph, "Auroral Phenomenology and Magnetospheric Processes: Earth And Other Planets", [10.1029/2012GM001231]

    Gilson, M., J. Raeder, E. Donovan, Y. S. Ge, and E. L. Kepko. 2012. "Global simulation of protoon precipitation due to field line curvature during substorms." J. Geophys. Res., [10.1029/2012JA017562]

    Frisell, N., J. Baker, J. Ruohoniemi, et al. L. Clausen, Z. Kale, I. Rae, E. L. Kepko, K. Oksavik, R. Greenwald, and M. West. 2011. "First radar observations in the vicinity of the plasmapause of pulsed ionospheric ionospheric flows generated by bursty bulk flows." Geophys Res. Lett., 38:

    Kepko, E. L., E. Spanswick, V. Angelopoulos, et al. E. Donovan, J. McFadden, K.-H. Glassmeier, J. Raeder, and H. J. Singer. 2010. "Equatorward moving auroral signatures of a flow burst observed prior to auroral onset." Geophys. Res. Lett.,

    Kepko, L., E. Spanswick, V. Angelopoulos, et al. E. Donovan, J. McFadden, K.-H. Glassmeier, J. Raeder, and H. J. Singer. 2009. "Equatorward moving auroral signatures of a flow burst observed prior to auroral onset." Geophysical Research Letters, 36: [24104-10.1029/2009GL041476]

    Kepko, E. L., H. E. Spence, and D. F. Smart. 2009. "Solar cosmic ray events observed in Greenland ice cores: 1940-1950." Advances in Space Research,

    Kepko, E. L., H. E. Spence, D. F. Smart, and M. A. Shea. 2009. "Interhemispheric observations of impulsive nitrate enhancements associated with the four large ground-level solar cosmic ray events (1940-1950)." Journal of Atmospheric and Solar-Terrestrial Physics, [10.1016/j.jastp.2009.07.002]

    Viall, N. M., E. L. Kepko, and H. E. Spence. 2009. "Relative occurrence rates and connection of discrete frequency oscillations in the solar wind density and dayside magnetosphere." J. Geophys. Res., 114 (A01201): [10.1029/2008JA013334]

    Viall, N. M., L. Kepko, and H. E. Spence. 2008. "Inherent length-scales of periodic solar wind number density structures." Journal of Geophysical Research (Space Physics), 113: [7101 10.1029/2007JA012881]

    Kepko, L., J. Raeder, V. Angelopoulos, et al. J. McFadden, D. Larson, H. U. Auster, W. Magnes, H. U. Frey, C. Carlson, M. Henderson, S. B. Mende, K. Yumoto, H. J. Singer, G. Parks, I. Mann, C. T. Russell, E. Donovan, and R. McPherron. 2008. "Highly periodic stormtime activations observed by THEMIS prior to substorm onset." Geophysical Research Letters, 35: [17-10.1029/2008GL034235]

    Gabrielse, C., V. Angelopoulos, A. Runov, et al. L. Kepko, K. H. Glassmeier, H. U. Auster, J. McFadden, C. W. Carlson, and D. Larson. 2008. "Propagation characteristics of plasma sheet oscillations during a small storm." Geophysical Research Letters, 35: [17-10.1029/2008GL033664]

    Kepko, E. L., H. E. Spence, M. A. Shea, D. F. Smart, and G. Dreschoff. 2008. "Observations of Impulsive Nitrate Enhancements Associated With Ground-Level Cosmic Ray Events 1-4 (1942-1949)." in Proceedings of the 30th International Cosmic Ray Conference,

    Viall-Kepko, N. M., E. L. Kepko, and H. E. Spence. 2008. "Inherent length-scales of periodic solar wind number density structures." J. Geophys. Res., 113 (A07101): [10.1029/2007JA012881]

    Kasper, J. C., H. Spence, J. B. Blake, et al. M. Golightly, L. Kepko, J. Mazur, T. Onsager, and L. Townsend. 2006. "Characterizing the evolution of radiation with the Cosmic Ray Telescope for the Effects of Radiation." 36th COSPAR Scientific Assembly, 36: 3480-.

    Kasper, J. C., H. Spence, J. B. Blake, et al. M. Golightly, L. Kepko, J. Mazur, T. Onsager, and L. Townsend. 2006. "CRaTER: the Cosmic Ray Telescope for the Effects of Radiation experiment on Lunar Reconnaissance Orbiter." 36th COSPAR Scientific Assembly, 36: 3381-.

    Smart, D. F., M. A. Shea, H. E. Spence, and L. Kepko. 2006. "Two groups of extremely large >30 MeV solar proton fluence events." Advances in Space Research, 37: 1734-1740 [10.1016/j.asr.2005.09.008]

    Kepko, L., M. G. Kivelson, R. L. McPherron, and H. E. Spence. 2004. "Relative timing of substorm onset phenomena." Journal of Geophysical Research (Space Physics), 109: [4203-10.1029/2003JA010285]

    Smart, D. F., M. A. Shea, H. E. Spence, and L. Kepko. 2004. "The Extremes in the Interplanetary Solar Proton Environment and the Two Classes of Solar Events Associated with Very Large > 30 MeV Solar Proton Fluence Events." 35th COSPAR Scientific Assembly, 35: 3266-.

    Kepko, L., and H. E. Spence. 2003. "Observations of discrete, global magnetospheric oscillations directly driven by solar wind density variations." Journal of Geophysical Research (Space Physics), 108: [1257-10.1029/2002JA009676]

    Kepko, L., H. E. Spence, and H. J. Singer. 2002. "ULF waves in the solar wind as direct drivers of magnetospheric pulsations." Geophysical Research Letters, 29: [1197-10.1029/2001GL014405]

    Kepko, L., M. G. Kivelson, and K. Yumoto. 2001. "Flow bursts, braking, and Pi2 pulsations." Journal of Geophysical Research, 106: 1903-1916 [10.1029/2000JA000158]

    Elphic, R. C., J. D. Means, R. C. Snare, et al. R. J. Strangeway, L. Kepko, and R. E. Ergun. 2001. "Magnetic Field Instruments for the Fast Auroral Snapshot Explorer." Space Science Reviews, 98: 151-168.

    Kepko, L., and R. L. McPherron. 2001. "Comment on “Evaluation of low-latitude Pi2 pulsations as indicators of substorm onset using Polar ultraviolet imagery” by K. Liou, et al.." J. Geophys. Res., 106 (A9): 18919-18922 [10.1029/2000JA000189]

    Strangeway, R. J., L. Kepko, R. C. Elphic, et al. C. W. Carlson, R. E. Ergun, J. P. McFadden, W. J. Peria, G. T. Delory, C. C. Chaston, M. Temerin, C. A. Cattell, E. Mobius, L. M. Kistler, D. M. Klumpar, W. K. Peterson, E. G. Shelley, and R. F. Pfaff. 1998. "FAST observations of VLF waves in the auroral zone: Evidence of very low plasma densities." Geophysical Research Letters, 25: 2065-2068 [10.1029/98GL00664]

    Elphic, R. C., J. W. Bonnell, R. J. Strangeway, et al. L. Kepko, R. E. Ergun, J. P. McFadden, C. W. Carlson, W. Peria, C. A. Cattell, D. Klumpar, E. Shelley, W. Peterson, E. Moebius, L. Kistler, and R. Pfaff. 1998. "The auroral current circuit and field-aligned currents observed by FAST." Geophysical Research Letters, 25: 2033-2036 [10.1029/98GL01158]

    Kivelson, M. G., K. K. Khurana, R. J. Walker, L. Kepko, and D. Xu. 1996. "Flux ropes, interhemispheric conjugacy, and magnetospheric current closure." Journal of Geophysical Research, 101: 27341-27350 [10.1029/96JA02220]

    Brief Bio

    While at NASA/GSFC, I have been fortunate to work on a number of different projects with a variety of roles. My current science interests are focused on understanding pre-onset auroral signatures during magnetospheric substorms, and understanding the source of periodic density structures in the solar wind. In addition to my science interests, I have worked with AETD to develop capabilities on Center to enable highly reliable, highly capable cubesats that can be used either as inexpensive science platforms or could be used to create constellations of satellites. I have been involved in a number of LCAS and OCT proposals, and was Co-I on the ASTRE Heliophysics Explorer, which was selected for Phase A study, losing to eventual winner ICON (PI Tom Immel). I serve on both the Heliophysics and Cross-Cutting Technologies Lines of Business. Finally, I volunteer extensively for community service, including co-chairing the 2012/13 Heliophysics Roadmap, being Editor of JGR - Space Physics (through 2017), and serving on numerous review panels.

    Prior to coming to Goddard, I was worked at both UNH and Boston University. I received my Ph.D. in Geophysics and Space Physics from UCLA, with a thesis entitled, "Transient Convection in the Earth's Magnetosphere and the Generation of Pi2 Pulsations" (Advisor Margaret Kivelson). I was awarded the AGU Fred L. Scarf award, given annually to a recent Ph.D. recipient for outstanding dissertation research that contributes directly to solar-planetary science, in 2002.

    Publications

    Refereed

    Di Matteo, S., U. Villante, N. Viall, L. Kepko, and S. Wallace. 2022. "On Differentiating Multiple Types of ULF Magnetospheric Waves in Response to Solar Wind Periodic Density Structures." Journal of Geophysical Research: Space Physics 127 (3): [10.1029/2021ja030144]

    Di Matteo, S., N. M. Viall, and L. Kepko. 2021. "Power Spectral Density Background Estimate and Signal Detection via the Multitaper Method." Journal of Geophysical Research: Space Physics 126 (2): e2020JA028748 [10.1029/2020ja028748]

    Kepko, L., and N. M. Viall. 2019. "The Source, Significance, and Magnetospheric Impact of Periodic Density Structures Within Stream Interaction Regions." Journal of Geophysical Research: Space Physics (In Press) [10.1029/2019ja026962]

    Di Matteo, S., N. M. Viall, L. Kepko, et al. S. Wallace, C. N. Arge, and P. MacNeice. 2019. "Helios Observations of Quasiperiodic Density Structures in the Slow Solar Wind at 0.3, 0.4, and 0.6 AU." Journal of Geophysical Research: Space Physics 124 (2): 837-860 [10.1029/2018ja026182]

    Kepko, L., N. Viall, S. K. Antiochos, et al. S. T. Lepri, J. C. Kasper, and M. Weberg. 2016. "Implications of L1 observations for slow solar wind formation by solar reconnection." Geophysical Research Letters 43 (9): 4089–4097 [10.1002/2016gl068607]

    Le, G., H. Lühr, B. J. Anderson, et al. R. J. Strangeway, C. T. Russell, H. Singer, J. A. Slavin, Y. Zhang, T. Huang, K. Bromund, P. J. Chi, G. Lu, D. Fischer, E. L. Kepko, H. K. Leinweber, W. Magnes, R. Nakamura, F. Plaschke, J. Park, J. Rauberg, C. Stolle, and R. B. Torbert. 2016. "Magnetopause erosion during the March 17, 2015, magnetic storm: Combined field-aligned currents, auroral oval, and magnetopause observations." Geophysical Research Letters 43 (6): 2396–2404 [10.1002/2016gl068257]

    Kissinger, J., L. Kepko, D. N. Baker, et al. S. Kanekal, W. Li, R. L. McPherron, and V. Angelopoulos. 2014. "The importance of storm time steady magnetospheric convection in determining the final relativistic electron flux level." JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 119 [10.1002/2014JA019948]

    Kepko, E. L., J. Slavin, K.-H. Glassmeier, and T. Sundberg. 2014. "The substorm current wedge at Earth and Mercury." AGU Monograph, "Magnetotails in the Solar System"

    Simoes, F., R. F. Pfaff, H. T. Freudenreich, et al. J. H. Klenzing, D. E. Rowland, K. Bromund, E. L. Kepko, G. Le, M. C. Liebrecht, S. C. Martin, and P. Uribe. 2013. "Equatorial ionosphere semiannual oscillation investigated from Schumann resonance measurements on board the C/NOFS satellite." Journal of Geophysical Research (Atmospheres) 118 12,045-12,051 [10.1002/jgrd.50797]

    Moore, T. E., M. O. Chandler, N. Buzulukova, et al. G. A. Collinson, E. L. Kepko, K. S. Garcia-Sage, M. G. Henderson, and M. I. Sitnov. 2013. "Snowplow - injection front effects." JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 118 6478-6488 [10.1002/jgra.50573]

    Moore, T. E., M. O. Chandler, N. Buzulukova, et al. G. A. Collinson, E. L. Kepko, K. S. Garcia-Sage, M. G. Henderson, and M. I. Sitnov. 2013. "'Snowplow' injection front effects." Journal of Geophysical Research (Space Physics) 118 6478-6488 [10.1002/jgra.50573]

    Kissinger, J., F. Wilder, R. L. McPherron, et al. T. S. Hsu, J. Bake, and E. L. Kepko. 2013. "Statistical occurrence and dynamics of the Harang discontinuity during steady magnetospheric convection." J. Geophys. Res. [10.1002/jgra.50503]

    Gilson, M. L., J. Raeder, E. Donovan, Y. S. Ge, and L. Kepko. 2012. "Global simulation of proton precipitation due to field line curvature during substorms." Journal of Geophysical Research (Space Physics) 117 [5216-10.1029/2012JA017562]

    Keiling, A., K. Shiokawa, V. Uritsky, et al. V. Sergeev, E. Zesta, E. L. Kepko, and N. Østgaard. 2012. "Auroral Signatures of the Dynamic Plasma Sheet, in Auroral Signatures of the Dynamic Plasma Sheet." AGU Monograph, "Auroral Phenomenology and Magnetospheric Processes: Earth And Other Planets" [10.1029/2012GM001231]

    Gilson, M., J. Raeder, E. Donovan, Y. S. Ge, and E. L. Kepko. 2012. "Global simulation of protoon precipitation due to field line curvature during substorms." J. Geophys. Res. [10.1029/2012JA017562]

    Frisell, N., J. Baker, J. Ruohoniemi, et al. L. Clausen, Z. Kale, I. Rae, E. L. Kepko, K. Oksavik, R. Greenwald, and M. West. 2011. "First radar observations in the vicinity of the plasmapause of pulsed ionospheric ionospheric flows generated by bursty bulk flows." Geophys Res. Lett. 38

    Kepko, E. L., E. Spanswick, V. Angelopoulos, et al. E. Donovan, J. McFadden, K.-H. Glassmeier, J. Raeder, and H. J. Singer. 2010. "Equatorward moving auroral signatures of a flow burst observed prior to auroral onset." Geophys. Res. Lett.

    Kepko, L., E. Spanswick, V. Angelopoulos, et al. E. Donovan, J. McFadden, K.-H. Glassmeier, J. Raeder, and H. J. Singer. 2009. "Equatorward moving auroral signatures of a flow burst observed prior to auroral onset." Geophysical Research Letters 36 [24104-10.1029/2009GL041476]

    Kepko, E. L., H. E. Spence, and D. F. Smart. 2009. "Solar cosmic ray events observed in Greenland ice cores: 1940-1950." Advances in Space Research

    Kepko, E. L., H. E. Spence, D. F. Smart, and M. A. Shea. 2009. "Interhemispheric observations of impulsive nitrate enhancements associated with the four large ground-level solar cosmic ray events (1940-1950)." Journal of Atmospheric and Solar-Terrestrial Physics [10.1016/j.jastp.2009.07.002]

    Viall, N. M., E. L. Kepko, and H. E. Spence. 2009. "Relative occurrence rates and connection of discrete frequency oscillations in the solar wind density and dayside magnetosphere." J. Geophys. Res. 114 (A01201): [10.1029/2008JA013334]

    Viall, N. M., L. Kepko, and H. E. Spence. 2008. "Inherent length-scales of periodic solar wind number density structures." Journal of Geophysical Research (Space Physics) 113 [7101 10.1029/2007JA012881]

    Kepko, L., J. Raeder, V. Angelopoulos, et al. J. McFadden, D. Larson, H. U. Auster, W. Magnes, H. U. Frey, C. Carlson, M. Henderson, S. B. Mende, K. Yumoto, H. J. Singer, G. Parks, I. Mann, C. T. Russell, E. Donovan, and R. McPherron. 2008. "Highly periodic stormtime activations observed by THEMIS prior to substorm onset." Geophysical Research Letters 35 [17-10.1029/2008GL034235]

    Gabrielse, C., V. Angelopoulos, A. Runov, et al. L. Kepko, K. H. Glassmeier, H. U. Auster, J. McFadden, C. W. Carlson, and D. Larson. 2008. "Propagation characteristics of plasma sheet oscillations during a small storm." Geophysical Research Letters 35 [17-10.1029/2008GL033664]

    Kepko, E. L., H. E. Spence, M. A. Shea, D. F. Smart, and G. Dreschoff. 2008. "Observations of Impulsive Nitrate Enhancements Associated With Ground-Level Cosmic Ray Events 1-4 (1942-1949)." in Proceedings of the 30th International Cosmic Ray Conference

    Viall-Kepko, N. M., E. L. Kepko, and H. E. Spence. 2008. "Inherent length-scales of periodic solar wind number density structures." J. Geophys. Res. 113 (A07101): [10.1029/2007JA012881]

    Kasper, J. C., H. Spence, J. B. Blake, et al. M. Golightly, L. Kepko, J. Mazur, T. Onsager, and L. Townsend. 2006. "Characterizing the evolution of radiation with the Cosmic Ray Telescope for the Effects of Radiation." 36th COSPAR Scientific Assembly 36 3480-

    Kasper, J. C., H. Spence, J. B. Blake, et al. M. Golightly, L. Kepko, J. Mazur, T. Onsager, and L. Townsend. 2006. "CRaTER: the Cosmic Ray Telescope for the Effects of Radiation experiment on Lunar Reconnaissance Orbiter." 36th COSPAR Scientific Assembly 36 3381-

    Smart, D. F., M. A. Shea, H. E. Spence, and L. Kepko. 2006. "Two groups of extremely large >30 MeV solar proton fluence events." Advances in Space Research 37 1734-1740 [10.1016/j.asr.2005.09.008]

    Kepko, L., M. G. Kivelson, R. L. McPherron, and H. E. Spence. 2004. "Relative timing of substorm onset phenomena." Journal of Geophysical Research (Space Physics) 109 [4203-10.1029/2003JA010285]

    Smart, D. F., M. A. Shea, H. E. Spence, and L. Kepko. 2004. "The Extremes in the Interplanetary Solar Proton Environment and the Two Classes of Solar Events Associated with Very Large > 30 MeV Solar Proton Fluence Events." 35th COSPAR Scientific Assembly 35 3266-

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