Differential flow between solar wind protons and alpha particles: First WIND observations

1996 ◽  
Vol 23 (10) ◽  
pp. 1183-1186 ◽  
Author(s):  
J. T. Steinberg ◽  
A. J. Lazarus ◽  
K. W. Ogilvie ◽  
R. Lepping ◽  
J. Byrnes
Keyword(s):  
Solar Wind ◽  
Alpha Particles ◽  
Differential Flow

Proton Beam Abundance Variations and Their Relation to Alpha Particle Properties

2021 ◽  
Vol 923 (2) ◽  
pp. 170
Author(s):  
Tereza Ďurovcová ◽  
Jana Šafránková ◽  
Zdeněk Němeček
Keyword(s):  
Solar Wind ◽  
Proton Beam ◽  
Alpha Particle ◽  
Source Region ◽  
Radial Distance ◽  
Alpha Particles ◽  
Momentum Balance ◽  
Particle Interactions ◽  
Coulomb Collisions ◽  
Particle Properties

Abstract Less abundant but still dynamically important solar wind components are the proton beam and alpha particles, which usually contribute similarly to the total ion momentum. The main characteristics of alpha particles are determined by the solar wind source region, but the origin of the proton beam and its properties are still not fully explained. We use the plasma data measured in situ on the path from 0.3 to 1 au (Helios 1 and 2) and focus on the proton beam development with an increasing radial distance as well as on the connection between the proton beam and alpha particle properties. We found that the proton beam relative abundance increases with increasing distance from the Sun in the collisionally young streams. Among the mechanisms suggested for beam creation, we have identified the wave–particle interactions with obliquely propagating Alfvén modes being consistent with observations. As the solar wind streams get collisionally older, the proton beam decay gradually dominates and the beam abundance is reduced. In search for responsible mechanisms, we found that the content of alpha particles is correlated with the proton beam abundance, and this effect is more pronounced in the fast solar wind streams during the solar maximum. We suggest that Coulomb collisions are the main agent leading to merging of the proton beam and core. We are also showing that the variations of the proton beam abundance are correlated with a decrease of the alpha particle velocity in order to maintain the total momentum balance in the solar wind frame.

scholarly journals Dependence of Ion Temperatures on Alpha–Proton Differential Flow Vector and Heating Mechanisms in the Solar Wind

2020 ◽  
Vol 889 (1) ◽  
pp. L14
Author(s):  
G. Q. Zhao ◽  
H. Q. Feng ◽  
D. J. Wu ◽  
J. Huang ◽  
Y. Zhao ◽  
...  
Keyword(s):  
Solar Wind ◽  
Flow Vector ◽  
Differential Flow

TAUS measurements of non-gyrotropic distribution functions of solar wind alpha particles

1996 ◽  
Author(s):  
H. F. Astudillo ◽  
E. Marsch ◽  
S. Livi ◽  
H. Rosenbauer
Keyword(s):  
Solar Wind ◽  
Distribution Functions ◽  
Alpha Particles

scholarly journals Capture of solar wind alpha-particles by the Martian atmosphere

2009 ◽  
Vol 36 (23) ◽  
Author(s):  
G. M. Chanteur ◽  
E. Dubinin ◽  
R. Modolo ◽  
M. Fraenz
Keyword(s):  
Solar Wind ◽  
Martian Atmosphere ◽  
Alpha Particles

Alfvén waves, alpha particles, and pickup ions in the solar wind

1996 ◽  
Author(s):  
B. E. Goldstein ◽  
M. Neugebauer ◽  
E. J. Smith
Keyword(s):  
Solar Wind ◽  
Alpha Particles ◽  
Pickup Ions
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