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Three of the most important and most puzzling features of the Sun's atmosphere are the smoothness of the closed field corona, the accumulation of magnetic shear at photospheric polarity inversion lines (PIL), and the complexity of the slow…

Solar and Stellar Astrophysics · Physics 2015-06-12 S. K. Antiochos

The formation of the observed core-halo feature in the solar wind electron velocity distribution function is a long-time puzzle. In this letter based on the current knowledge of nanoflares we show that the nanoflare-accelerated electron…

Solar and Stellar Astrophysics · Physics 2015-06-23 H. Che , M. Goldstein

Meridional circulation regulates the Sun's interior dynamics and magnetism. While it is well accepted that meridional flows are poleward at the Sun's surface, helioseismic observations have yet to provide a definitive answer for the depth…

Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p-modes with a 3 mHz frequency peak dominate the lower…

Above the top of the solar corona, the young slow solar wind transitions from low-beta, magnetically structured flow dominated by radial structures, to high-beta, less structured flow dominated by hydrodynamics. This transition, long…

Solar and Stellar Astrophysics · Physics 2016-09-21 C. E. DeForest , W. H. Matthaeus , N. M. Viall , S. R. Cranmer

Properties of the Sun's interior can be determined accurately from helioseismological measurements of solar oscillations. These measurements, however, are in conflict with photospheric elemental abundances derived using 3-D hydrodynamic…

Solar and Stellar Astrophysics · Physics 2018-07-18 David H. Brooks , Deborah Baker , Lidia van Driel-Gesztelyi , Harry P. Warren

Current models of the solar wind must approximate (or ignore) the small-scale dynamics within the solar atmosphere, however these are likely important in shaping the emerging wave-turbulence spectrum and ultimately heating/accelerating the…

Solar and Stellar Astrophysics · Physics 2022-09-28 Adam J. Finley , Sacha A. Brun , Mats Carlsson , Mikolaj Szydlarski , Viggo Hansteen , Munehito Shoda

Using data collected by the Indian Mars Orbiter Mission in October 2021, we investigated coronal regions of the Sun by analyzing the Doppler spectral width of radio signals to estimate solar wind velocity. A simplified equation is…

Solar and Stellar Astrophysics · Physics 2025-04-02 Keshav Aggarwal , R. K. Choudhary , Abhirup Datta , Roopa M. V. , Bijoy K. Dai

The solar wind is connected to the Sun's atmosphere by flux tubes that are rooted in an ever-changing pattern of positive and negative magnetic polarities on the surface. Observations indicate that the magnetic field is filamentary and…

Solar and Stellar Astrophysics · Physics 2015-06-15 Steven R. Cranmer , Adriaan A. van Ballegooijen , Lauren N. Woolsey

Models for the origin of the slow solar wind must account for two seemingly contradictory observations: The slow wind has the composition of the closed field corona, implying that it originates from the continuous opening and closing of…

Solar and Stellar Astrophysics · Physics 2015-05-27 S. K. Antiochos , Z. Mikić , V. S. Titov , R. Lionello , J. A. Linker

The connection between nuclear fusion in the Sun's core and solar irradiance is obscured among other things by uncertainty over the mechanism of coronal heating. Data for solar wind density and velocity, sunspot number, and EUV flux suggest…

Solar and Stellar Astrophysics · Physics 2016-09-16 Claudio Vita-Finzi

When observed at 1 AU, slow solar wind is typically considered to have originated in source regions with magnetic topologies that are intermittently open to the heliosphere. Fast wind is typically considered to have originated in source…

Solar and Stellar Astrophysics · Physics 2025-08-27 B. L. Alterman , Y. J. Rivera , S. T. Lepri , J. M. Raines , R. D'Amicis

The effect of viscosity and of converging flows on the formation of blobs in the slow solar wind is analysed by means of resistive MHD simulations. The regions above coronal streamers where blobs are formed (Sheeley et al., 1997) are…

Astrophysics · Physics 2015-05-13 Giovanni Lapenta , Anna Lisa Restante

Because of its distinctive compositional properties and variability, low-speed ($\lesssim 450$ km s$^{-1}$) solar wind is widely believed to originate from coronal streamers, unlike high-speed wind, which comes from coronal holes. An…

Solar and Stellar Astrophysics · Physics 2021-04-16 Y. -M. Wang , Y. -K. Ko

Heavy element and helium diffusion are both included for the first time in this series of papers on precise solar models, along with improvements in the input data for nuclear reaction rates, the solar luminosity, the solar age, heavy…

High Energy Physics - Phenomenology · Physics 2008-11-26 John N. Bahcall , M. H. Pinsonneault

We have performed a three-dimensional magnetohydrodynamic simulation to study the emergence of a twisted magnetic flux tube from -20,000 km of the solar convection zone to the corona through the photosphere and the chromosphere. The middle…

Solar and Stellar Astrophysics · Physics 2015-06-03 S. Toriumi , T. Yokoyama

The origin of the Sun's slow wind and its inherent variability remain unknown, but there is increasing evidence that interactions between closed and open magnetic flux in the corona play a major role. This paper studies the dynamic…

Solar and Stellar Astrophysics · Physics 2026-04-01 Sahel Dey , David I. Pontin , Spiro K. Antiochos

We present a new global model of the solar corona, including the low corona, the transition region and the top of chromosphere. The realistic 3D magnetic field is simulated using the data from the photospheric magnetic field measurements.…

Slow solar wind is typically characterized as having low Alfv\'enicity, but the occasional occurrence of highly Alfv\'enic slow solar wind (HASSW) raises questions about its source regions and evolution. In this work, we conduct a…