Observations of the 2019 April 4 Solar Energetic Particle Event at the Parker Solar Probe

摘要: A solar energetic particle event was detected by the Integrated Science Investigation of Sun (IS⊙IS) instrument suite on Parker Solar Probe (PSP) 2019 April 4 when spacecraft inside 0.17 au and less than 1 day before its second perihelion, providing an opportunity to study acceleration transport unprecedentedly close source. The very small, with peak MeV proton intensities ~0.3 particles (cm² sr s MeV)⁻¹, undetectable above background levels at energies 10 or in detectors au. It strongly anisotropic, flowing outward from up 30 times greater those inward persisting throughout event. Temporal association between increases small brightness surges extreme-ultraviolet observed TErrestrial RElations Observatory, which were also accompanied type III radio emission seen Electromagnetic Fields PSP, indicates that source this active region nearly 80° east nominal PSP magnetic footpoint. This suggests field lines expanded over a wide longitudinal range photosphere corona.