Long-term variations of the solar wind proton parameters

1974 ◽  
Vol 79 (34) ◽  
pp. 5095-5108 ◽  
Author(s):  
L. Diodato ◽  
G. Moreno ◽  
C. Signorini ◽  
K. W. Ogilvie
Keyword(s):  
Solar Wind ◽  
Solar Wind Proton ◽  
Long Term Variations

scholarly journals Long-Term Independence of Solar Wind Polytropic Index on Plasma Flow Speed

Entropy ◽  
2018 ◽  
Vol 20 (10) ◽  
pp. 799 ◽  
Author(s):  
George Livadiotis
Keyword(s):  
Solar Wind ◽  
Plasma Flow ◽  
Solar Wind Speed ◽  
Solar Wind Plasma ◽  
Flow Speed ◽  
Polytropic Index ◽  
Solar Cycles ◽  
Solar Wind Proton ◽  
Plasma Flow Speed

The paper derives the polytropic indices over the last two solar cycles (years 1995–2017) for the solar wind proton plasma near Earth (~1 AU). We use ~92-s datasets of proton plasma moments (speed, density, and temperature), measured from the Solar Wind Experiment instrument onboard Wind spacecraft, to estimate the moving averages of the polytropic index, as well as their weighted means and standard errors as a function of the solar wind speed and the year of measurements. The derived long-term behavior of the polytropic index agrees with the results of other previous methods. In particular, we find that the polytropic index remains quasi-constant with respect to the plasma flow speed, in agreement with earlier analyses of solar wind plasma. It is shown that most of the fluctuations of the polytropic index appear in the fast solar wind. The polytropic index remains quasi-constant, despite the frequent entropic variations. Therefore, on an annual basis, the polytropic index of the solar wind proton plasma near ~1 AU can be considered independent of the plasma flow speed. The estimated all-year weighted mean and its standard error is γ = 1.86 ± 0.09.

scholarly journals LONG-TERM TRENDS IN THE SOLAR WIND PROTON MEASUREMENTS

2016 ◽  
Vol 832 (1) ◽  
pp. 66 ◽  
Author(s):  
Heather A. Elliott ◽  
David J. McComas ◽  
Craig E. DeForest
Keyword(s):  
Solar Wind ◽  
Solar Wind Proton ◽  
Long Term Trends

scholarly journals Long‐Term Variations in Solar Wind Parameters, Magnetopause Location, and Geomagnetic Activity Over the Last Five Solar Cycles

2019 ◽  
Vol 124 (6) ◽  
pp. 4049-4063 ◽  
Author(s):  
A. A. Samsonov ◽  
Y. V. Bogdanova ◽  
G. Branduardi‐Raymont ◽  
J. Safrankova ◽  
Z. Nemecek ◽  
...  
Keyword(s):  
Solar Wind ◽  
Geomagnetic Activity ◽  
Solar Cycles ◽  
Solar Wind Parameters ◽  
Long Term Variations

scholarly journals Long-term variations in the heliosphere

2018 ◽  
Vol 13 (S340) ◽  
pp. 108-114
Author(s):  
Mathew J. Owens ◽  
Mike Lockwood ◽  
Pete Riley ◽  
Luke Barnard
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Space Weather ◽  
Ice Sheets ◽  
Solar Dynamo ◽  
Heliospheric Magnetic Field ◽  
Future Space ◽  
Cosmogenic Radionuclide ◽  
Long Term Variations

AbstractReconstructions of long-term solar variability underpin our understanding of the solar dynamo, potential tropospheric climate implications and future space weather scenarios. Prior to direct spacecraft measurements of the heliospheric magnetic field (HMF) and solar wind, accurate annual reconstructions are possible using geomagnetic and sunspot records. On longer timescales, information about the HMF can be extracted from cosmogenic radionuclide records, particularly 14C in ancient trees and 10Be in ice sheets. These proxies, and what they reveal about the HMF and solar wind, are briefly reviewed here.

scholarly journals Long-term variations of the flow direction and angular momentum of the solar wind observed by Helios

2001 ◽  
Vol 366 (1) ◽  
pp. 331-338 ◽  
Author(s):  
K. Scherer ◽  
E. Marsch ◽  
R. Schwenn ◽  
H. Rosenbauer
Keyword(s):  
Solar Wind ◽  
Angular Momentum ◽  
Flow Direction ◽  
Long Term Variations

Long-term variations of selected solar wind properties: Imp 6, 7, and 8 results

1978 ◽  
Vol 83 (A5) ◽  
pp. 2177 ◽  
Author(s):  
W. C. Feldman ◽  
J. R. Asbridge ◽  
S. J. Bame ◽  
J. T. Gosling
Keyword(s):  
Solar Wind ◽  
Long Term Variations
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