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Related papers: Velocity Profiles in the Solar Corona from Multi-I…

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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…

Recent observations from Parker Solar Probe have revealed that the solar wind has a highly variable structure. How this complex behaviour is formed in the solar corona is not yet known, since it requires omnipresent fluctuations, which…

This work consists of two parts: the first devoted to the study of the heating of the magnetically confined Solar Corona, and the second to the acceleration of the Slow Solar Wind. Direct 3D reduced MHD simulations are presented. They model…

Solar and Stellar Astrophysics · Physics 2010-01-13 A. F. Rappazzo

The elemental composition of the Sun's hot atmosphere, the corona, shows a distinctive pattern that is different than the underlying surface, or photosphere (Pottasch 1963). Elements that are easy to ionize in the chromosphere are enhanced…

Solar and Stellar Astrophysics · Physics 2022-05-18 David H. Brooks , Deborah Baker , Lidia van Driel-Gesztelyi , Harry P. Warren , Stephanie L. Yardley

This paper presents results of comparison between observations of coronal holes in the UV (SOHO EIT) and microwave emission (17, 5.7 GHz, 327 and 150.9 MHz, NoRH, SSRT and Nancy radioheliographs), and solar wind parameters, according to the…

Solar and Stellar Astrophysics · Physics 2015-05-20 D. Prosovetsky , I. Myagkova

Plasma outflows from the edges of active regions have been suggested as a possible source of the slow solar wind. Spectroscopic measurements show that these outflows have an enhanced elemental composition, which is a distinct signature of…

We update two kinds of results obtained with the SWAN instrument on board SOHO. First, we use H cell data recorded in 2001 and derive the H flow direction in the same way we performed the study at solar minimum. We compare with the Helium…

Solar and Stellar Astrophysics · Physics 2014-05-15 Rosine Lallement , Eric Quémerais , Dimitra Koutroumpa , Jean-Loup Bertaux , Stéphane Ferron , Walter Schmidt

High-speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium-level geomagnetic storm activity. Modeling high-speed solar wind streams is thus an essential element…

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…

Solar and Stellar Astrophysics · Physics 2016-06-01 David H. Brooks , Ignacio Ugarte-Urra , Harry P. Warren

Measurement of the solar wind speed near the Sun is important for understanding the acceleration mechanism of the solar wind. In this study, we determine 2D solar wind speeds from 6 to 26 solar radii by applying Fourier motion filters to…

Solar and Stellar Astrophysics · Physics 2018-08-29 Il-Hyun Cho , Yong-Jae Moon , Valery M. Nakariakov , Su-Chan Bong , Jin-Yi Lee , Donguk Song , Harim Lee , Kyung-Suk Cho

Context. Several physical properties of solar polar plumes have been identified by different published studies, however such studies are rare and sometimes in disagreement. Aims. The purpose of the present work is to analyze a set of…

Solar and Stellar Astrophysics · Physics 2020-11-18 L. Zangrilli , S. M. Giordano

The acceleration of the young solar wind is studied using the first 17 encounters of Parker Solar Probe. We identify wind intervals from different source regions: coronal hole (CH) interiors, streamers, and low Mach number boundary layers…

Solar and Stellar Astrophysics · Physics 2024-10-23 Yiming Jiao , Ying D. Liu , Wenshuai Cheng , Hao Ran , Rui Wang

This paper reviews our growing understanding of the physics behind coronal heating (in open-field regions) and the acceleration of the solar wind. Many new insights have come from the last solar cycle's worth of observations and theoretical…

Solar and Stellar Astrophysics · Physics 2010-02-02 Steven R. Cranmer , John L. Kohl , Mari Paz Miralles , Adriaan A. van Ballegooijen

One of the basic properties of the solar wind, that is the high speed of the fast wind, is still not satisfactorily explained. This is mainly due to the theoretical difficulty of treating weakly collisional plasmas. The fluid approach…

Astrophysics · Physics 2009-11-11 I. Zouganelis , N. Meyer-Vernet , S. Landi , M. Maksimovic , F. Pantellini

Observation of Interplanetary Scintillation (IPS) provides an important and effective way to study the solar wind and the space weather. A series of IPS observations were conducted by the Five-hundred-meter Aperture Spherical radio…

Solar and Stellar Astrophysics · Physics 2022-08-03 Li-Jia Liu , Bo Peng , Lei Yu , Bin Liu , Ji-Guang Lu , Ye-Zhao Yu , Hong-Wei Xi , Ming Xiong , O. Chang

Empirical solar wind speed models play an important role in enabling space weather forecasting with low computational cost. Among these, one model called WS model is based on the asymptotic expansion factor. However, it is known that it…

Solar and Stellar Astrophysics · Physics 2026-01-30 Kyogo Tokoro , Munehito Shoda , Shinsuke Imada

One of the most interesting discoveries of the X-ray Telescope and EUV Imaging Spectrometer (EIS) on board the Hinode solar observatory is the presence of persistent high temperature high speed outflows from the edges of active regions.…

Solar and Stellar Astrophysics · Physics 2015-05-20 David H. Brooks , Harry P. Warren

The acceleration of thermal solar wind protons at spherical interplanetary shocks driven by coronal mass ejections is investigated. The solar wind velocity distribution is represented using $\kappa$-functions, which are transformed in…

Space Physics · Physics 2019-08-07 P. L. Prinsloo , R. D. Strauss , J. A. le Roux

The solar wind consists of continuous streams of charged particles that escape into the heliosphere from the Sun, and is split into fast and slow components, with the fast wind emerging from the interiors of coronal holes. Near the ecliptic…

Solar and Stellar Astrophysics · Physics 2022-11-28 L. P. Chitta , D. B. Seaton , C. Downs , C. E. DeForest , A. K. Higginson

In a recent study, we took advantage of a highly tilted coronal neutral sheet to show that density structures, extending radially over several solar radii (Rs), are released in the forming slow solar wind approximately 4-5 Rs above the…

Solar and Stellar Astrophysics · Physics 2017-12-20 Eduardo Sanchez-Diaz , Alexis P. Rouillard , Jackie A. Davies , Benoit Lavraud , Rui F. Pinto , Emilia Kilpua