scholarly journals Solar Wind Helium Abundance as a Function of Speed and Heliographic Latitude: Variation through a Solar Cycle

2007 ◽  
Vol 660 (1) ◽  
pp. 901-910 ◽  
Author(s):  
Justin C. Kasper ◽  
Michael L. Stevens ◽  
Alan J. Lazarus ◽  
John T. Steinberg ◽  
Keith. W. Ogilvie
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Helium Abundance ◽  
Heliographic Latitude ◽  
Latitude Variation

scholarly journals Solar Wind Helium Abundance Heralds Solar Cycle Onset

2021 ◽  
Author(s):  
Benjamin L Alterman ◽  
Justin C Kasper ◽  
Robert J Leamon ◽  
Scott W McIntosh
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Cycle Length ◽  
Phase Lag ◽  
Helium Abundance ◽  
Solar Cycles ◽  
Wind Speeds ◽  
Solar Wind Acceleration ◽  
Solar Cycle Length

Abstract We study the solar wind helium-to-hydrogen abundance's ( A He ) relationship to solar cycle onset. Using OMNI/Lo data, we show that A He increases prior to sunspot number (SSN) minima. We also identify a rapid depletion and recovery in A He that occurs directly prior to cycle onset. This A He Shutoff happens at approximately the same time across solar wind speeds ( v sw ) and the time between successive A He shutoffs is typically on the order of the corresponding solar cycle length. In contrast to A He 's v sw -dependent phase lag with respect to SSN (Alterman and Kasper, 2019), A He Shutoff's concurrence across v sw likely implies it is independent of solar wind acceleration and driven by a mechanism near or below the photosphere. Using Brightpoint (BP) measurements to provide context, we infer that this shutoff is likely related to the overlap of adjacent solar cycles and the equatorial flux cancelation of the older, extended solar cycle during solar minima.

Observation-based Ionization Rates during the Decade of IBEX Observations

2020 ◽  
Author(s):  
Justyna M. Sokol
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Data Interpretation ◽  
Interstellar Gas ◽  
Heliographic Latitude ◽  
The Earth ◽  
Similarities And Differences ◽  
Cycle 24 ◽  
Helium Neon ◽  
Ionization Rates

<p><span>Solar wind and EUV flux are dominant ionization factors for the interstellar gas inside the heliosphere. They vary in time with the solar cycle and with heliographic latitude. The modulation of the solar ionizing factors affects the fluxes of interstellar neutral (ISN) gas and energetic neutral atoms (ENAs) on their way from heliospheric boundaries to IBEX in the Earth’s vicinity. IBEX has been measuring ISN gas of hydrogen, helium, neon, and oxygen, as well as hydrogen ENAs since the beginning of the solar cycle 24. Most of the ISN gas species observed by IBEX-Lo are prone to variations in time of the in-ecliptic ionization rates. In case of H ENAs, variations of the out-of-ecliptic solar wind are significant for data interpretation.</span></p><p><span>We present a model of ionization rates based on available observations of the solar wind and the solar EUV flux. We follow methodology discussed by Sokół et al. 2019 </span><span>(ApJ</span><span><span> 872:57)</span></span><span>, however with data selection revised according to recent data releases. We focus on ionization rates for various species in and out of the ecliptic during the decade of IBEX observations. We discuss similarities and differences in the dominant ionization processes, the latitudinal modulation, and the evolution in time. </span></p>

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 Solar Wind Helium Abundance Heralds Solar Cycle Onset

Solar Physics ◽  
2021 ◽  
Vol 296 (4) ◽  
Author(s):  
Benjamin L. Alterman ◽  
Justin C. Kasper ◽  
Robert J. Leamon ◽  
Scott W. McIntosh
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Helium Abundance

The solar wind helium abundance: Variation with wind speed and the solar cycle

2001 ◽  
Vol 28 (14) ◽  
pp. 2767-2770 ◽  
Author(s):  
Matthias R. Aellig ◽  
Alan J. Lazarus ◽  
John T. Steinberg
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Wind Speed ◽  
Helium Abundance ◽  
Abundance Variation

Ulysses solar wind plasma observations during the declining phase of solar cycle 22

1995 ◽  
Vol 16 (9) ◽  
pp. 85-94 ◽  
Author(s):  
J.L. Phillips ◽  
S.J. Bame ◽  
W.C. Feldman ◽  
J.T. Gosling ◽  
C.M. Hammond ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Solar Wind Plasma

scholarly journals Mars Under Primordial Solar Wind Conditions: Mars Express Observations of the Strongest CME Detected at Mars Under Solar Cycle #24 and its Impact on Atmospheric Ion Escape

2017 ◽  
Vol 44 (21) ◽  
Author(s):  
Robin Ramstad ◽  
Stas Barabash ◽  
Yoshifumi Futaana ◽  
Masatoshi Yamauchi ◽  
Hans Nilsson ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Mars Express ◽  
Ion Escape ◽  
Solar Cycle 24 ◽  
Cycle 24
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