Solar cycle dependence of global distribution of solar wind speed

1990 ◽  
Vol 53 (3-4) ◽  
pp. 173-222 ◽  
Author(s):  
Masayoshi Kojima ◽  
Takakiyo Kakinuma
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Wind Speed ◽  
Solar Wind Speed ◽  
Global Distribution ◽  
Cycle Dependence

North-south asymmetry in global distribution of the solar wind speed during 1985-2013

2015 ◽  
Vol 120 (5) ◽  
pp. 3283-3296 ◽  
Author(s):  
Munetoshi Tokumaru ◽  
Ken'ichi Fujiki ◽  
Tomoya Iju
Keyword(s):  
Solar Wind ◽  
Wind Speed ◽  
Solar Wind Speed ◽  
Global Distribution ◽  
South Asymmetry

An unusual aspect of solar wind speed variations during solar cycle 20

1977 ◽  
Vol 82 (22) ◽  
pp. 3311-3314 ◽  
Author(s):  
J. T. Gosling ◽  
J. R. Asbridge ◽  
S. J. Bame
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Wind Speed ◽  
Solar Wind Speed

EVOLUTION OF THE RELATIONSHIPS BETWEEN HELIUM ABUNDANCE, MINOR ION CHARGE STATE, AND SOLAR WIND SPEED OVER THE SOLAR CYCLE

2012 ◽  
Vol 745 (2) ◽  
pp. 162 ◽  
Author(s):  
J. C. Kasper ◽  
M. L. Stevens ◽  
K. E. Korreck ◽  
B. A. Maruca ◽  
K. K. Kiefer ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Wind Speed ◽  
Charge State ◽  
Solar Wind Speed ◽  
Helium Abundance

scholarly journals Evolution of the Solar Wind Speed with Heliocentric Distance and Solar Cycle. Surprises from Ulysses and Unexpectedness from Observations of the Solar Corona

2018 ◽  
Vol 44 (9) ◽  
pp. 840-853 ◽  
Author(s):  
O. V. Khabarova ◽  
V. N. Obridko ◽  
R. A. Kislov ◽  
H. V. Malova ◽  
A. Bemporad ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Wind Speed ◽  
Solar Corona ◽  
Heliocentric Distance ◽  
Solar Wind Speed

Solar cycle evolution of the solar wind speed distribution from 1985 to 2008

2010 ◽  
Vol 115 (A4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Munetoshi Tokumaru ◽  
Masayoshi Kojima ◽  
Ken'ichi Fujiki
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Wind Speed ◽  
Solar Wind Speed ◽  
Speed Distribution ◽  
Wind Speed Distribution

Global Distribution of the Solar Wind Speed Reconstructed from Improved Tomographic Analysis of Interplanetary Scintillation Observations between 1985 and 2019

2021 ◽  
Vol 922 (1) ◽  
pp. 73
Author(s):  
Munetoshi Tokumaru ◽  
Ken’ichi Fujiki ◽  
Masayoshi Kojima ◽  
Kazumasa Iwai
Keyword(s):  
Solar Wind ◽  
Wind Speed ◽  
Power Index ◽  
Solar Wind Speed ◽  
Global Distribution ◽  
Interplanetary Scintillation ◽  
Wind Speeds ◽  
In Situ Observations

Abstract Computer-assisted tomography (CAT) for interplanetary scintillation (IPS) observations enables the determination of the global distribution of solar wind speed. We compared solar wind speeds derived from the CAT analysis of IPS observations between 1985 and 2019 with in situ observations conducted by the near-Earth and Ulysses spacecraft. From this comparison, we found that solar wind speeds from the IPS observations for 2009–2019 were systematically higher than the in situ observations, whereas those for the period until 2008 were in good agreement with the in situ observations. Further, we found that the discrepancy between IPS and the in situ observations is improved by changing the power index of the empirical relation between the solar wind speed and density fluctuations. The CAT analysis using an optimal value for the power index determined from the comparison between IPS and in situ observations revealed long-term variations in the solar wind speed distribution over three cycles, leading to a better understanding of the time-varying global heliosphere. We found that polar solar winds become highly anisotropic at the Cycle 24/25 minimum, which is a peculiar aspect of this minimum. The IPS observations showed general agreement with the Parker Solar Probe observations around the perihelion of Orbit 1; this supports the reliability of the CAT analysis. The results of this study suggest that the physical properties of solar wind microturbulence may vary with a long-term decline in the solar activity, which provides important implication on the solar wind acceleration.

Sign in / Sign up

Export Citation Format

Share Document