scholarly journals A Comparison of Alpha Particle and Proton Beam Differential Flows in Collisionally Young Solar Wind

2018 ◽  
Vol 864 (2) ◽  
pp. 112 ◽  
Author(s):  
B. L. Alterman ◽  
Justin C. Kasper ◽  
Michael L. Stevens ◽  
Andriy Koval
Keyword(s):  
Solar Wind ◽  
Proton Beam ◽  
Alpha Particle

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.

Linear and Nonlinear Effects of Proton Temperature Anisotropy on Proton-beam Instability in the Solar Wind

2021 ◽  
Vol 916 (1) ◽  
pp. 30
Author(s):  
L. Xiang ◽  
K. H. Lee ◽  
D. J. Wu ◽  
H. W. Yu ◽  
L. C. Lee
Keyword(s):  
Solar Wind ◽  
Proton Beam ◽  
Nonlinear Effects ◽  
Beam Instability ◽  
Temperature Anisotropy ◽  
Proton Temperature ◽  
Linear And Nonlinear

Velocity Distributions and Proton Beam Production in the Solar Wind

2010 ◽  
Author(s):  
Viviane Pierrard ◽  
Yuriy Voitenko ◽  
M. Maksimovic ◽  
K. Issautier ◽  
N. Meyer-Vernet ◽  
...  
Keyword(s):  
Solar Wind ◽  
Proton Beam ◽  
Beam Production

scholarly journals Solar wind ion scattering by Alfvén-cyclotron fluctuations: ion temperature anisotropies versus relative alpha particle densities

2006 ◽  
Vol 8 ◽  
pp. 17-17 ◽  
Author(s):  
S Peter Gary ◽  
Lin Yin ◽  
Dan Winske ◽  
John T Steinberg ◽  
Ruth M Skoug
Keyword(s):  
Solar Wind ◽  
Alpha Particle ◽  
Ion Scattering ◽  
Ion Temperature

scholarly journals Reduced proton and alpha particle precipitations at Mars during solar wind pressure pulses: Mars Express results

2013 ◽  
Vol 118 (6) ◽  
pp. 3421-3429 ◽  
Author(s):  
C. Diéval ◽  
G. Stenberg ◽  
H. Nilsson ◽  
N. J. T. Edberg ◽  
S. Barabash
Keyword(s):  
Solar Wind ◽  
Alpha Particle ◽  
Wind Pressure ◽  
Mars Express ◽  
Pressure Pulses ◽  
Solar Wind Pressure

Study of alpha particle properties across rarefaction regions

2021 ◽  
Author(s):  
Tereza Durovcova ◽  
Jana Šafránková ◽  
Zdeněk Němeček
Keyword(s):  
Solar Wind ◽  
Wind Speed ◽  
Alpha Particle ◽  
Solar Wind Speed ◽  
Coronal Holes ◽  
Distribution Functions ◽  
Alpha Particles ◽  
Slow Solar Wind ◽  
The Sun ◽  
Wind Source

<p>Two large-scale interaction regions between the fast solar wind emanating from coronal holes and the slow solar wind coming from streamer belt are usually distinguished. When the fast stream pushes up against the slow solar wind ahead of it, a compressed interaction region that co-rotates with the Sun (CIR) is created. It was already shown that the relative abundance of alpha particles, which usually serve as one of solar wind source identifiers can change within this region. By symmetry, when the fast stream outruns the slow stream, a corotating rarefaction region (CRR) is formed. CRRs are characterized by a monotonic decrease of the solar wind speed, and they are associated with the regions of small longitudinal extent on the Sun. In our study, we use near-Earth measurements complemented by observations at different heliocentric distances, and focus on the behavior of alpha particles in the CRRs because we found that the large variations of the relative helium abundance (AHe) can also be observed there. Unlike in the CIRs, these variations are usually not connected with the solar wind speed and alpha-proton relative drift changes. We thus apply a superposed-epoch analysis of identified CRRs with a motivation to determine the global profile of alpha particle parameters through these regions. Next, we concentrate on the cases with largest AHe variations and investigate whether they can be associated with the changes of the solar wind source region or whether there is a relation between the AHe variations and the non-thermal features in the proton velocity distribution functions like the temperature anisotropy and/or presence of the proton beam.</p>

scholarly journals The solar wind alpha-particle content as a clue for the origin of slow flows

1998 ◽  
Vol 25 (15) ◽  
pp. 2921-2924 ◽  
Author(s):  
B. Bavassano ◽  
R. Bruno ◽  
E. Pietropaolo
Keyword(s):  
Solar Wind ◽  
Alpha Particle ◽  
Particle Content ◽  
Slow Flows

Magnetosonic instability driven by an alpha particle beam in the solar wind

1978 ◽  
Vol 83 (A12) ◽  
pp. 5750 ◽  
Author(s):  
P. Revathy
Keyword(s):  
Solar Wind ◽  
Alpha Particle ◽  
Particle Beam

Variations of solar wind proton and alpha-particle hydrodynamic parameters: Prognoz 7 observations

1989 ◽  
Vol 9 (4) ◽  
pp. 123-126 ◽  
Author(s):  
Yu.I. Yermolaev ◽  
V.V. Stupin ◽  
G.N. Zastenker ◽  
G.P. Khamitov ◽  
I. Kozak
Keyword(s):  
Solar Wind ◽  
Alpha Particle ◽  
Solar Wind Proton ◽  
Hydrodynamic Parameters

Ulysses Observations of Solar Wind Proton and Alpha Particle Temperatures and Anisotropies from 1 to 5 AU

1993 ◽  
Vol 13 (6) ◽  
pp. 294
Author(s):  
B.E. Goldstein ◽  
S.J. Bame ◽  
J.L. Phillips ◽  
J.T. Gosling ◽  
D.J. McComas ◽  
...  
Keyword(s):  
Solar Wind ◽  
Alpha Particle ◽  
Solar Wind Proton
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