Radial Evolution of Sunward Strahl Electrons in the Inner Heliosphere

0538667 - ASÚ 2021 RIV NL eng J - Journal Article
Macneil, A.R. - Owens, M.J. - Lockwood, M. - Štverák, Štěpán - Owen, C.
Radial Evolution of Sunward Strahl Electrons in the Inner Heliosphere.
Solar Physics. Roč. 295, č. 2 (2020), č. článku 16. ISSN 0038-0938. E-ISSN 1573-093X
Institutional support: RVO:67985815
Keywords : magnetic fields * interplanetary * magnetic reconnection
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 2.671, year: 2020
Method of publishing: Open access

We test if the pitch angle distribution (PAD) properties of sunward-propagating strahl are different from those of outward strahl. We perform a statistical study of strahl observed by the Helios spacecraft, over heliocentric distances spanning approximate to 0.3 - 1 AU. We find that sunward strahl PADs are broader and less intense than their outward directed counterparts - particularly at distances 0.3 - 0.75 AU. This is consistent with sunward strahl being subject to additional, path-length dependent, scattering in comparison to outward strahl. We conclude that the longer and more variable path from the Sun to the spacecraft, along inverted magnetic field, leads to this additional scattering. The results also suggest that the relative importance of scattering along this additional path length drops off with heliocentric distance. These results can be explained by a relatively simple, constant-rate, scattering process.
Permanent Link: http://hdl.handle.net/11104/0316421