Solar Energetic Particles and Seed Populations Observed by Parker Solar Probe at ∼0.5 au: Observations and Modeling of the April 21, 2019 Energetic Particle Event

Nathan Schwadron1,2, Stuart D Bale3, Anthony W Case4, Eric R Christian5, Christina Cohen6, Alan C Cummings6, Andrew D Davis7, Wouter Christiaan de Wet2, Mihir Indrajit Desai8,9, Colin J Joyce1, Joe Giacalone10, Matthew Gorby2, Bernd Heber11, Matthew E Hill12, Michail Karavolos13, Justin Christophe Kasper14, Kelly E Korreck4, Stamatios Mike Krimigis12, Allan Wayne Labrador6, Richard A Leske6, Robert J. MacDowall5, Olga Malandraki15, William H Matthaeus16, Leila M Mays5, David J McComas1, Ralph L McNutt Jr12, Richard A Mewaldt6, Donald G Mitchell12, Jonathan T. Niehof2, Dusan Odstrcil5,17, Marc Pulupa3, Bala Poduval2, Arik Posner18, Jamie Sue Rankin1, Edward C Stone6, Jamey R Szalay1, Mark E Wiedenbeck6 and Reka Moldovan Winslow2, (1)Princeton University, Department of Astrophysical Sciences, Princeton, NJ, United States, (2)University of New Hampshire, Durham, NH, United States, (3)University of California, Berkeley, Space Sciences Laboratory, Berkeley, CA, United States, (4)Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States, (5)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (6)California Institute of Technology, Pasadena, CA, United States, (7)Research Mathematician, Cold Region Research and Engineering Laboratory, Hanover, NH, United States, (8)Southwest Research Institute, San Antonio, TX, United States, (9)University of Texas at San Antonio, San Antonio, TX, United States, (10)University of Arizona, Tucson, AZ, United States, (11)University of Kiel, Kiel, Germany, (12)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (13)National Observatory of Athens, Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, Athens, Greece, (14)University of Michigan, Ann Arbor, MI, United States, (15)National Observatory of Athens, IAASARS, Athens, Greece, (16)University of Delaware, Newark, DE, United States, (17)George Mason University Fairfax, Fairfax, VA, United States, (18)NASA Headquarters, SMD/Heliophysics Division, Washington, DC, United States