Associate Lab chief
Ionospheric, Thermospheric, Mesospheric Lab
NASA/Goddard Space Flight Center
She/her/hers
Brief Bio:
Following graduation from Augsburg College in Minneapolis MN Alexa Halford went on to receive a Masters in Astronomy and Planetary Sciences from University of Colorado at Boulder and a Ph.D. in Physics at the University of Newcastle Australia. Shortly after completing her Ph.D. work, Halford won a highly competitive “Visiting Young Scientist” fellowship from Dartmouth College. She then moved to the Aerospace Corporation and is now the deputy director of the Ionosphere, Thermosphere, Mesosphere lab at NASA Goddard Space Flight Center. At Goddard she works as the Heliophysics and Space Weather Goddard strategic lead for Artemis, the deputy PI for petitSat, and on several other committees/working groups associated with space weather.
Dr. Halford’s expertise for this ISSI team resides in wave-particle interactions and their impact on loss from the magnetosphere to the ionosphere and upper atmosphere.
Selected Relevant Publications: (Orcid https://orcid.org/0000-0002-5383-4602)
Shumko M, Gallardo-Lacourt B, Halford AJ, Blum LW, Liang J, Miyoshi Y, Hosokawa K, Donovan E, Mann IR, Murphy K, Spanswick EL, Blake JB, Looper MD and Gillies DM (2022) Proton aurora and relativistic electron microbursts scattered by electromagnetic ion cyclotron waves. Front. Astron. Space Sci. 9:975123. doi: 10.3389/fspas.2022.975123
Remya, B., D.G. Sibeck, J.M. Ruohoniemi, B. Kunduri, A.J. Halford, G. D. Reeves, and R. V. Reddy, Association between EMIC wave occurrence and enhanced convection periods during ion injections, 2020, DOI: 10.1029/2019GL085676, Geophysical Research Letters
Bingley, L., V. Angelopoulos, D. Sibeck, X.-J. Zhang, A.J. Halford, The evolution of a pitch-angle ”bite-out” scattering signature caused by EMIC wave activity: A case study, (2019), https://doi.org/10.1029/2018JA026292, J.Geophys.Res
Brito, T., S. Elkington, A. Halford, ”A review on ULF waves and their affect on radiation belt dynamics”, The Dynamic Loss of Earth’s Radiation Belts: From loss in the magnetosphere to particle precipitation in the atmosphere, 2019, edited by A. Jaynes and M. Usanova
Lessard, M. R., K. Paulson, H. Spence, C. Weaver, M. J. Engebretson, R. Millan, L. A. Woodger, A.J. Halford , R. Horne, C. J. Rodger, and A. Hendry, “Generation of EMIC
Waves and Effects on Particle Precipitation During a Moderate Storm with Bz > 0”, (2019), https://doi.org/10.1029/2019JA026477 J.Geophys.Res
Medeiros, C., V.M. Souza, L.E.A. Vieira, D.G. Sibeck, A.J. Halford , L.A. Da Silva, L.R. Alves, J.P. Marchezi, R. S. Dallaqua, PR. Jauer, M. Rockenbach, O. Mendes, M. V. Alves, and A. Dal Lago, “Investigating an Unusual Pitch Angle Distribution During the Electron Flux Dropout on September 12, 2014”, (2019),p. 36, vol 872, number 1, 10.3847/1538-4357/aaf970 The Astrophysical Journal
Remya, B., D. G. Sibeck, A. J. Halford, K. R. Murphy G. D. Reeves H. J. Singer J. R. Wygant, G. Farinas Perez S. A. Thaller,“Ion injection triggered EMIC waves in the Earth’s magnetosphere”, (2018), J.Geophys.Res, 123, 4921?4938, https://doi.org/10.1029/2018JA025354
Cliverd, M., C. Rodger, M. McCarthy, R. Millan, L. Blum, N. Cobbett, J. Brundell, D. Danskin, A. J. Halford, “Investigating energetic electron precipitation through combining ground-based, and balloon observations” (2017) J. Geophys. Res., 10.1002/2016JA022812
Zhang, J., A.J. Halford, A. Saikin, C-L Huang, H. Spence, B. Larsen, G. Reeves, R. Millan, C. Smith, R. Torbert, W. Kurth, C. Kletzing, J.B. Blake, J. Fennel, D. Baker, ”EMIC waves and associated relativistic electron precipitation on 25-26 January 2013”, (2016), J. Geophys. Res., 10.1002/2016JA022918
Halford, A.J., B. J. Fraser, S. Morley, S. Elkington, A. Chan, ”Dependence of EMIC wave parameters during quiet, geomagnetic storm, and geomagnetic storm phase times” (2016), J. Geophys. Res. Energetic Electron Precipitation special issue, 10.1002/2016JA022694
Blum, L.W., A.J. Halford, R. Millan, J.W. Bonnell, J. Goldstein, M. Usanova, M. Engebretson, M. Ohnsted, G. Reeves, and H. Singer, (2015), ”Observations of coincident EMIC wave activity and dusk side energetic electron precipitation on 18-19 January 2013”, Geophys. Res.Lett., doi: 10.1002/2015GL065245
Woodger, L.A., A.J. Halford, R.M. Milan, M.P. McCarthy, D.M. Smith, J.G. Sample, B.Anderson, and the BARREL Team, (2015), ”A Summary of the BARREL Campaigns: Technique for studying electron precipitation”, J. Geophys. Res. 2015 Van Allen Probes Special Issue, doi: 10.1002/2014JA020874
Halford, A.J., B. J. Fraser,S. K. Morley, (2015) ”EMIC waves and plasmaspheric and plume density enhancements: CRRES results”, J. Geophys. Res., 120, doi: 10.1002/2014JA020338
Blum, L. W., Q. Schiller, X. Li, R. Millan, A. Halford, and L. Woodger (2013), ”New conjunctive CubeSat and balloon measurements to quantify rapid energetic electron precipitation”, Geophys. Res. Lett., 40, 5833?5837, doi:10.1002/2013GL058546.
Millan, R. M., M. P. McCarthy, J. G. Sample, D. M. Smith, L. D. Thompson, D. G. McGaw, L. A. Woodger, J. G. Hewitt, M. D. Comess, K. B. Yando, A. X. Liang, B. A. Anderson, N. R. Knezek, W. Z. Rexroad, J. M. Scheiman, G. S. Bowers, A. J. Halford, A. B. Collier, M. A. Cliverd, R. P. Lin, M. K. Hudson, (2013), ”The Balloon Array for RBSP Relativistic Electron Losses (BARREL)”, Space Sci. Rev., 179, 503?530, doi:10.1007/s11214-013-9971-z.
Halford, A.J., B. J. Fraser, and S. K. Morley (2010), ”EMIC wave activity during geomagnetic storm and nonstorm periods: CRRES results”, J. Geophys. Res., 115, A12248, doi 10.1029/2010JA015716.
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