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Related papers: Element Abundances: A New Diagnostic for the Solar…

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We present a further investigation into the increased ionization observed in element charge states in the fast solar wind compared to its coronal hole source regions. Once ions begin to be perpendicularly heated by ion cyclotron waves and…

Astrophysics · Physics 2011-02-11 J. Martin Laming , Susan T. Lepri

The activity indicators of M dwarfs are distinctly different for early and late types. The coronae of early M dwarfs display high X-ray luminosities and temperatures, a pronounced inverse FIP effect, and frequent flaring to the extent that…

Astrophysics · Physics 2009-11-13 C. Liefke , J. -U. Ness , J. H. M. M. Schmitt , A. Maggio

We update the SOHO/SWAN H Lyman-alpha brightness analysis to cover the 1996-2008 time interval. A forward model applied to the intensity maps provides the latitude and time dependence of the interstellar Hydrogen ionisation rate over more…

Solar and Stellar Astrophysics · Physics 2010-03-23 Rosine Lallement , Eric Quemerais , Philippe Lamy , Jean-Loup Bertaux , Stephane Ferron , Walter Schmidt

Alpha-proton differential flow ($V_{\alpha p}$) of coronal mass ejections (CMEs) and solar wind from the Sun to 1 au and beyond could influence the instantaneous correspondence of absolute abundances of alpha particles (He$^{2+}$/H$^{+}$)…

Solar and Stellar Astrophysics · Physics 2024-09-18 Xuechao Zhang , Hongqiang Song , Xiaoqian Wang , Leping Li , Hui Fu , Rui Wang , Yao Chen

We investigate the properties and relationship between Doppler-velocity fluctuations and intensity fluctuations in the off-limb quiet Sun corona. These are expected to reflect the properties of Alfvenic and compressive waves, respectively.…

Solar and Stellar Astrophysics · Physics 2025-03-21 Michael Hahn , Xiangrong Fu , Stefan J. Hofmeister , Yifan Huang , Alexandros Koukras , Daniel Wolf Savin

Alfv\'enic fluctuations are very common features in the solar wind and are found especially within the main portion of fast wind streams while the slow wind usually is less Alfv\'enic and more variable. In general, fast and slow wind show…

Space Physics · Physics 2018-12-19 Raffaella D'Amicis , Lorenzo Matteini , Roberto Bruno

The Parker Solar Probe (PSP) mission presents a unique opportunity to study the near-Sun solar wind closer than any previous spacecraft. During its fourth and fifth solar encounters, PSP had the same orbital trajectory, meaning that solar…

In the corona, plasma is accelerated to hundreds of kilometers per second, and heated to temperatures hundreds of times hotter than the Sun's surface, before it escapes to form the solar wind. Decades of space-based experiments have shown…

We review recent work on 111 Fe-rich impulsive solar energetic ($\sim$ 3 MeV/nuc) particle (SEP) events observed from 1994 to 2013. Strong elemental abundance enhancements scale with A/Q, the ion mass-to-charge ratio, as (A/Q)$^{\alpha}$,…

Solar and Stellar Astrophysics · Physics 2015-10-01 Stephen Kahler , Donald Reames , Edward Cliver

Solar energetic particles (SEPs) are produced in two fundamental ways: at magnetic reconnection sites in solar jets and at collisionless shock waves driven by fast coronal mass ejections (CMEs). "Impulsive" SEP events, on open field lines…

Solar and Stellar Astrophysics · Physics 2026-02-24 Donald V Reames

The role of interchange reconnection as a drive mechanism for the solar wind is explored by solving the global magnetic-field-aligned equations describing wind acceleration. Boundary conditions in the low corona, including a…

Solar and Stellar Astrophysics · Physics 2023-08-16 J. F. Drake , S. D. Bale , M. Swisdak , N. E. Raouafi , M. Velli

In contrast with the fast solar wind, that originates in coronal holes, the source of the slow solar wind is still debated. Often intermittent and enriched with low FIP elements -- akin to what is observed in closed coronal loops -- the…

Solar and Stellar Astrophysics · Physics 2020-06-03 Victor Réville , Marco Velli , Alexis Rouillard , Benoit Lavraud , Anna Tenerani , Chen Shi , Antoine Strugarek

An important aspect of solar energetic particle (SEP) events is their source populations. Elemental abundance enhancements of impulsive SEP events, originating in presumed coronal reconnection episodes, can be fitted to steep power laws of…

Solar and Stellar Astrophysics · Physics 2024-03-12 Jin-Yi Lee , Stephen Kahler , John C. Raymond , Yuan-Kuen Ko

The abundance of potassium is derived from X-ray lines observed during flares by the RESIK instrument on the solar mission CORONAS-F between 3.53 A and 3.57 A. The lines include those emitted by He-like K and Li-like K dielectronic…

Solar and Stellar Astrophysics · Physics 2015-05-14 J. Sylwester , B. Sylwester , K. J. H. Phillips , V. D. Kuznetsov

We present a measurement of the abundance of Fe relative to H in the solar corona using a technique which differs from previous spectroscopic and solar wind measurements. Our method combines EUV line data from the CDS spectrometer on SOHO…

Astrophysics · Physics 2016-08-30 S. M. White , R. J. Thomas , J. W. Brosius , M. R. Kundu

Using spectra obtained by the EIS instrument onboard Hinode, we present a detailed spatially resolved abundance map of an active region (AR)-coronal hole (CH) complex that covers an area of 359 arcsec x 485 arcsec. The abundance map…

Solar and Stellar Astrophysics · Physics 2015-06-17 D. Baker , D. H. Brooks , P. Demoulin , L. van Driel-Gesztelyi , L. M. Green , K. Steed , J. Carlyle

Solar coronal plasma composition is typically characterized by first ionization potential (FIP) bias. Using spectra obtained by Hinode's EUV Imaging Spectrometer (EIS) instrument, we present a series of large-scale, spatially resolved…

Solar and Stellar Astrophysics · Physics 2015-06-23 D. Baker , D. H. Brooks , P. Démoulin , S. L. Yardley , L. van Driel-Gesztelyi , D. M. Long , L. M. Green

Fast and slow solar wind have distinct properties linked to their solar sources.Alfv\'enic slow wind complicates the usual speed-based classification, especially at intermediate speeds. Solar Orbiter's Solar Wind Analyzer (SWA) offers…

In solar energetic particle (SEP) events, the power-law dependence of element abundance enhancements on their mass-to-charge ratios A/Q provides a new tool that measures the combined rigidity dependences from both acceleration and…

Solar and Stellar Astrophysics · Physics 2020-08-18 Donald V. Reames

A key goal of the Solar Orbiter mission is to connect elemental abundance measurements of the solar wind enveloping the spacecraft with EUV spectroscopic observations of their solar sources, but this is not an easy exercise. Observations…