Jovian electrons and the solar wind during the minimum of the 23rd–24th solar activity cycle

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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MAGNETIC STRUCTIONS AND SOLAR WIND ACCORDING TO THE ACE/SWEPAM DATA IN THE DECLINE PHASE OF THE 24TH SOLAR ACTIVITY CYCLE

Proceedings of the 22nd All-Russia Conference on Solar and Solar-Terrestrial Physics ◽

10.31725/0552-5829-2018-43-46 ◽

2018 ◽

Cited By ~ 1

Author(s):

Z.S. Akhtemov ◽

◽

Yu.T. Tsap ◽

◽

Keyword(s):

Solar Wind ◽

Solar Activity ◽

Activity Cycle ◽

Solar Activity Cycle ◽

Decline Phase

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Are Solar Wind Measurements of Different Spacecraft Consistent?

Symposium - International Astronomical Union ◽

10.1017/s0074180900067486 ◽

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.

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Relationship between the fluxes of relativistic electrons at geosynchronous orbit and the level of ULF activity on the Earth’s surface and in the solar wind during the 23rd solar activity cycle

Cosmic Research ◽

10.1134/s0010952512020086 ◽

2012 ◽

Vol 50 (2) ◽

pp. 124-140 ◽

Cited By ~ 12

Author(s):

A. S. Potapov ◽

B. Tsegmed ◽

L. V. Ryzhakova

Keyword(s):

Solar Wind ◽

Solar Activity ◽

Activity Cycle ◽

Solar Activity Cycle ◽

Geosynchronous Orbit ◽

Relativistic Electrons ◽

23Rd Solar Activity Cycle

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Variations of the IMFBz component over a solar activity cycle for different regimes of solar wind formation

Astronomische Nachrichten ◽

10.1002/asna.2103160205 ◽

1995 ◽

Vol 316 (2) ◽

pp. 105-111 ◽

Cited By ~ 1

Author(s):

V. A. Kovalenko ◽

S. I. Molodykh

Keyword(s):

Solar Wind ◽

Solar Activity ◽

Activity Cycle ◽

Solar Activity Cycle

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INFLUENCE OF THE ß SOLAR WIND PARAMETER ON STATISTICAL CHARACTERISTICS OF THE Ap INDEX IN THE SOLAR ACTIVITY CYCLE

Solar-Terrestrial Physics ◽

10.12737/stp-54201906 ◽

2019 ◽

Vol 5 (4) ◽

pp. 46-52

Author(s):

Oleg Zotov ◽

Boris Klain ◽

Nadezhda Kurazhkovskaya

Keyword(s):

Solar Wind ◽

Solar Activity ◽

Activity Cycle ◽

Solar Activity Cycle ◽

Statistical Characteristics ◽

Solar Wind Parameter ◽

Power Functions ◽

Trigger Effect ◽

Chaotic Modes ◽

Ap Index

We have studied the effect of the β solar wind parameter (equal to the ratio of the plasma pressure to the magnetic pressure) on statistical characteristics of the Ap index reflecting the triggering behavior of the activity of Earth’s magnetosphere. The trigger effect of the dynamics of magnetospheric activity consists in the abrupt transition from the periodic mode to the chaotic mode in the solar activity cycle. It is shown that cumulative amplitude distribution functions and power spectra of the Ap index of both the periodic and chaotic modes are well approximated by power and exponential functions respectively. At the same time, the indices of power functions and the indices characterizing the slope of the Ap index spectrum differ significantly in magnitude for the periodic and chaotic modes. We have found that Ap nonlinearly depends on β for both the modes of magnetospheric dynamics. The maximum of the Ap index amplitude for periodic modes is observed when β>1; and for chaotic ones, when β<1. In almost every cycle of solar activity, the energy of the Ap index fluctuations of chaotic modes is higher than that of periodic ones. The results indicate intermittency and its associated turbulence of magnetospheric activity. The exponential character of the spectral density of the Ap index suggests that the behavior of magnetospheric activity is determined by its internal dynamics, which can be described by a finite number of deterministic equations. The trigger effect of magnetospheric activity is assumed to be due to the angle of inclination of the axis of the solar magnetic dipole to the ecliptic plane, on which the dynamics of the β parameter in the solar activity cycle depends.

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