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相关论文: The Evolution of Heavy Ion Abundances with Solar A…

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Traditionally, fast solar wind is considered to originate in solar source regions that are continuously open to the heliosphere and slow wind originates in regions that are intermittently open to it. In fast wind, the gradient of the solar…

空间物理 · 物理学 2025-12-29 B. L. Alterman , R. D'Amicis

The Helium abundance, defined as $A_{He}=n_{He}/n_{H}\times 100$, is $\sim$8.5 in the photosphere and seldom exceeds 5 in fast solar wind. Previous statistics have demonstrated that $A_{He}$ in slow solar wind correlates tightly with…

太阳与恒星天体物理 · 物理学 2022-02-09 Hongqiang Song , Xin Cheng , Leping Li , Jie Zhang , Yao Chen

We present and discuss the strong correspondence between evolution of the emission length scale in the lower transition region and in situ measurements of the fast solar wind composition during this most recent solar minimum. We combine…

太阳与恒星天体物理 · 物理学 2015-05-30 Scott W. McIntosh , Kandace K. Kiefer , Robert J. Leamon , Justin C. Kasper , Michael S. Stevens

The two-state solar wind paradigm is based on observations showing that slow and fast solar wind have distinct properties like helium abundances, kinetic signatures, elemental composition, and charge-state ratios. Nominally, the fast wind…

太阳与恒星天体物理 · 物理学 2025-03-28 B. L. Alterman , R. D'Amicis

We study the solar wind helium-to-hydrogen abundance's ($A_\mathrm{He}$) relationship to solar cycle onset. Using OMNI/Lo data, we show that $A_\mathrm{He}$ increases prior to sunspot number (SSN) minima. We also identify a rapid depletion…

太阳与恒星天体物理 · 物理学 2021-04-12 B. L. Alterman , Justin C. Kasper , Robert J. Leamon , Scott W. McIntosh

We study the relationship between solar wind helium to hydrogen abundance ratio ($A_\mathrm{He}$), solar wind speed ($v_\mathrm{SW}$), and sunspot number (SSN) over solar cycles 23 and 24. This is the first full 22-year Hale cycle measured…

空间物理 · 物理学 2019-07-01 B. L. Alterman , Justin C. Kasper

The solar wind is typically categorized as fast and slow based on the measured speed ($v_\mathrm{sw}$). The separation between these two regimes is often set between 400 and 600 km/s without a rigorous definition. Observations of the solar…

太阳与恒星天体物理 · 物理学 2025-02-19 B. L. Alterman , Y. J. Rivera , S. T. Lepri , R. M. Raines

Two main models have been developed to explain the mechanisms of release, heating and acceleration of the nascent solar wind, the wave-turbulence-driven (WTD) models and reconnection-loop-opening (RLO) models, in which the plasma release…

太阳与恒星天体物理 · 物理学 2018-05-23 Hui Fu , Maria S. Madjarska , Bo Li , LiDong Xia , ZhengHua Huang

Studies of patterns of abundance enhancements of elements, relative to solar-coronal abundances, in large solar energetic-particle (SEP) events, and of their power-law dependence on the mass-to-charge ratio A/Q of the ions, have been used…

太阳与恒星天体物理 · 物理学 2018-02-15 Donald V. Reames

The relative abundance of alpha particles with respect to proton, usually expressed as $A_{He}$ = ($n_\alpha/n_p$)*100, is known to respond to solar activity although changes in its behaviour in the last four solar cycles are not known. In…

太阳与恒星天体物理 · 物理学 2021-02-24 Yogesh , D. Chakrabarty , N. Srivastava

Acceleration and transport of solar energetic particles (SEPs) causes their abundances, measured at constant velocity, to be enhanced or suppressed as a function of each ion's magnetic rigidity, and hence its atomic mass-to-charge ratio…

太阳与恒星天体物理 · 物理学 2024-02-19 Donald V. Reames

The abundance of helium ($A_{He}$) in the solar wind exhibits variations typically in the range from 2-5% with respect to solar cycle activity and solar wind velocity. However, there are instances where the observed $A_{He}$ is…

太阳与恒星天体物理 · 物理学 2024-10-08 Yogesh , N. Gopalswamy , D. Chakrabarty , Parisa Mostafavi , Seiji Yashiro , Nandita Srivastava , Leon Ofman

Solar coronal holes are sources of high-speed solar wind streams, which cause persistent geomagnetic activity especially at high latitudes. Here we estimate seasonal solar wind speeds at 1 AU for the last 100 years using high-latitude…

空间物理 · 物理学 2017-02-22 Kalevi Mursula , Lauri Holappa , Renata Lukianova

Solar winds originate from the Sun and can be classified as fast or slow. Fast solar winds come from coronal holes at the solar poles, while slow solar winds may originate from the equatorial region or streamers. Spicules are jet-like…

太阳与恒星天体物理 · 物理学 2024-12-25 R. Sadeghi , E. Tavabi

Parker Solar Probe is a mission designed to explore properties of the solar wind closer than ever before. Detailed particle observations from the Solar Probe Cup (SPC) have primarily focused on examining the proton population in the solar…

Element settling inside the Sun now becomes detectable from the comparison of the observed oscillation modes with the results of the theoretical models. This settling is due, not only to gravitation, but also to thermal diffusion and…

天体物理学 · 物理学 2009-10-30 Sylvie Vauclair

Fast (>700 km/s) and slow (~400 km/s) winds stream from the Sun, permeate the heliosphere and influence the near-Earth environment. While the fast wind is known to emanate primarily from polar coronal holes, the source of the slow wind…

太阳与恒星天体物理 · 物理学 2016-06-01 David H. Brooks , Ignacio Ugarte-Urra , Harry P. Warren

This is a study of abundances of the elements He, C, N, O, Ne, Mg, Si, S, Ar, Ca, and Fe in solar energetic particles (SEPs) in the 2 - 15 MeV amu-1 region measured on the Wind spacecraft during 54 large SEP events occurring between…

太阳与恒星天体物理 · 物理学 2015-06-16 Donald V. Reames

Abundances of elements comprising solar energetic particles (SEPs) come with two very different patterns. Historically called "impulsive" and "gradual" events, they have been studied for 40 years, 20 years by the Wind spacecraft. Gradual…

太阳与恒星天体物理 · 物理学 2015-01-06 Donald V. Reames

The recent downward revision of solar photospheric abundances of Oxygen and other heavy elements has resulted in serious discrepancies between solar models and solar structure as determined through helioseismology. In this work we…

天体物理学 · 物理学 2009-11-11 H. M. Antia , Sarbani Basu
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