scholarly journals Are Solar Wind Measurements of Different Spacecraft Consistent?

1980 ◽  
Vol 91 ◽  
pp. 151-154
Author(s):  
R. Steinitz ◽  
M. Eyni
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Boundary Conditions ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
The Other ◽  
The Sun ◽  
Spatial Gradients ◽  
Wind Measurements ◽  
The One

Results of solar wind measurements by different spacecraft are not always in full accord. Such measurements are in general not from one and the same distance r from the sun, nor are they taken at the same phase of the solar activity cycle. One would like to be able to discriminate between spacecraft calibration effects on the one hand, and solar wind variations which reflect true spatial gradients or changing boundary conditions at the sun on the other hand. Accordingly, we examine in this paper the possibility of reconciling the apparent discrepancies.

TIME VARIATIONS IN KAMIOKANDE SOLAR NEUTRINO DATA

1991 ◽  
Vol 06 (22) ◽  
pp. 2003-2007 ◽  
Author(s):  
PROBHAS RAYCHAUDHURI
Keyword(s):  
Solar Activity ◽  
Solar Neutrino ◽  
Statistical Significance ◽  
Neutrino Flux ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Neutrino Experiment ◽  
The Sun ◽  
Flux Data ◽  
Solar Neutrino Flux

Solar neutrino flux (Eν ≥ 7.5 MeV ) data from 1st January to April 1990 as measured in Kamiokande solar neutrino experiment have been analyzed statistically and have found that the solar neutrino data varies with the solar activity cycle with very high statistical significance (> 98% confidence level). Average solar neutrino flux data in the sunspot minimum range cannot be equal to twice the average solar neutrino flux data in the sunspot maximum range, which suggests that the neutrino flip through the magnetic field of the convection zone of the sun is not responsible for the solar neutrino flux variation. Thus the variation of solar neutrino flux with the solar activity cycle suggests that the solar activity cycle is due to the pulsating character of the nuclear energy generation inside the core of the sun.

Solar Wind Variation with the Cycle

2000 ◽  
Vol 179 ◽  
pp. 423-429
Author(s):  
I. S. Veselovsky ◽  
A. V. Dmitriev ◽  
A. V. Suvorova ◽  
M. V. Tarsina
Keyword(s):  
Solar Wind ◽  
Coronal Holes ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Time Dependent ◽  
Solar Cycles ◽  
Solar Wind Density ◽  
Plasma Parameters ◽  
Decadal Variations ◽  
Wind Measurements

AbstractThe cyclic evolution of the heliospheric plasma parameters is related to the time-dependent boundary conditions in the solar corona. “Minimal” coronal configurations correspond to the regular appearance of the tenuous, but hot and fast plasma streams from the large polar coronal holes. The denser, but cooler and slower solar wind is adjacent to coronal streamers. Irregular dynamic manifestations are present in the corona and the solar wind everywhere and always. They follow the solar activity cycle rather well. Because of this, the direct and indirect solar wind measurements demonstrate clear variations in space and time according to the minimal, intermediate and maximal conditions of the cycles. The average solar wind density, velocity and temperature measured at the Earth’s orbit show specific decadal variations and trends, which are of the order of the first tens per cent during the last three solar cycles. Statistical, spectral and correlation characteristics of the solar wind are reviewed with the emphasis on the cycles.

Microwave Observations of the Sun During the 22nd Solar Activity Cycle — 17 GHz Radio Heliograph

1991 ◽  
pp. 345-350 ◽  
Author(s):  
K. Shibasaki ◽  
K. Kai ◽  
S. Enome ◽  
H. Nakajima ◽  
M. Nishio ◽  
...  
Keyword(s):  
Solar Activity ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
The Sun

Positional evolution of magnetic foci in the polar regions of the Sun with the phase of the solar activity cycle

2006 ◽  
Vol 50 (10) ◽  
pp. 834-841 ◽  
Author(s):  
D. V. Klepikov ◽  
B. P. Filippov ◽  
A. Ajabshirizadeh ◽  
Yu. V. Platov
Keyword(s):  
Solar Activity ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Polar Regions ◽  
The Sun

scholarly journals Disparity among low first ionization potential elements

2018 ◽  
Vol 619 ◽  
pp. A79 ◽  
Author(s):  
Verena Heidrich-Meisner ◽  
Lars Berger ◽  
Robert F. Wimmer-Schweingruber
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Ionization Potential ◽  
Charge State ◽  
Qualitative Difference ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Slow Solar Wind ◽  
Activity Maximum ◽  
First Ionization Potential

Context. The elemental composition of the solar wind differs from the solar photospheric composition. Elements with low first ionization potential (FIP) appear enhanced compared to O in the solar wind relative to the respective photospheric abundances. This so-called FIP effect is different in the slow solar wind and the coronal hole wind. However, under the same plasma conditions, for elements with similar FIPs such as Mg, Si, and Fe, comparable enhancements are expected. Aims. We scrutinize the assumption that the FIP effect is always similar for different low FIP elements, namely Mg, Si, and Fe. Methods. Here we investigate the dependency of the FIP effect of low FIP elements on the O7+/O6+ charge state ratio depending on time, that is the solar activity cycle, and solar wind type. In addition, we order the observed FIP ratios with respect to the O7+/O6+ charge state ratio into bins and analyze separately the respective distributions of the FIP ratio of Mg, Si, and Fe for each O7+/O6+ charge state ratio bin. Results. We observe that the FIP effect shows the same qualitative yearly behavior for Mg and Si, while Fe shows significant differences during the solar activity maximum and its declining phase. In each year, the FIP effect for Mg and Si always increases with increasing O7+/O6+ charge state ratio, but for high O7+/O6+ charge state ratios the FIP effect for Fe shows a qualitatively different behavior. During the years 2001–2006, instead of increasing with the O7+/O6+ charge state ratio, the Fe FIP ratio exhibits a broad peak or plateau. In addition, the FIP distribution per O7+/O6+ charge state bin is significantly broader for Fe than for Mg and Si. Conclusions. These observations support the conclusion that the elemental fractionation is only partly determined by FIP. In particular, the qualitative difference in behavior with increasing O7+/O6+ charge state ratio between Fe on the one hand and Mg and Si on the other hand is not yet well explained by models of fractionation.

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