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Thermal plasma of solar atmosphere includes a wide range of temperatures. This plasma is often quantified, both in observations and models, by a differential emission measure (DEM). DEM is a distribution of the thermal electron density…

Solar and Stellar Astrophysics · Physics 2021-06-23 Gregory D. Fleishman , Alexey A. Kuznetsov , Enrico Landi

We consider the problem of automatically (and robustly) isolating and extracting information about waves and oscillations observed in EUV image sequences of the solar corona with a view to near real-time application to data from the…

Astrophysics · Physics 2009-11-13 Scott W. McIntosh , Bart De Pontieu , Steven Tomczyk

One of the outstanding problems in all of space science is uncovering how the solar corona is heated to temperatures greater than 1 MK. Though studied for decades, one of the major difficulties in solving this problem has been unraveling…

Solar and Stellar Astrophysics · Physics 2015-06-15 Nicholeen M. Viall , James A. Klimchuk

Filaments may be mistaken for coronal holes when observed in extreme ultraviolet (EUV) images; however, a closer and more careful look reveals that their photometric properties are different. The combination of EUV images with photospheric…

Solar and Stellar Astrophysics · Physics 2017-04-04 Judith Palacios , Consuelo Cid , Elena Saiz , Yolanda Cerrato , Antonio Guerrero

EUV imaging observations from several space missions (SOHO/EIT, TRACE, and SDO/AIA) have revealed a presence of propagating intensity disturbances in solar coronal loops. These disturbances are typically interpreted as slow magnetoacoustic…

Solar and Stellar Astrophysics · Physics 2018-01-24 Elena Provornikova , Leon Ofman , Tongjiang Wang

Spatial information from stellar X-ray coronae can be inferred by use of scaling laws from the solar corona. This requires measurement of the physical parameters temperature and density. We concentrate on the newly available density…

Astrophysics · Physics 2009-11-10 J. -U. Ness , M. Güdel , J. H. M. M. Schmitt , M. Audard , A. Telleschi

A new dataset of atomic oxygen and molecular nitrogen number density profiles, along with thermospheric temperature profiles between 180 and 500 km, has been developed. These profiles are derived from solar occultation measurements made by…

Coronae express different facets of their energy release processes in different wavelength regions. While soft X-ray and EUV emission dominates the radiative losses of the thermal plasma, hard X-ray emission (>10 keV) can be produced from…

Astrophysics · Physics 2007-05-23 Manuel Guedel

Effects of radio-frequency power and driven frequency on the two-dimensional (axial and radial) distributions of electron density and temperature were experimentally investigated in low pressure capacitively coupled argon plasmas. The…

Plasma Physics · Physics 2020-10-22 Jidun Wu , Hao Zheng , Yanfei Wang , Fengzhu Zhou , Xiaojiang Huang

Traditional models of coronal oscillations rely on modelling the coronal structures that support them as compact cylindrical waveguides. Recently, an alternative model of the structure of the corona has been proposed, where the thin…

Solar and Stellar Astrophysics · Physics 2024-10-16 P. Kohutova , P. Antolin , M. Szydlarski , N. Poirier

Lava planets have non-global, condensible atmospheres similar to icy bodies within the solar system. Because they depend on interior dynamics, studying the atmospheres of lava planets can lead to understanding unique geological processes…

Earth and Planetary Astrophysics · Physics 2022-05-25 T. Giang Nguyen , Nicolas B. Cowan , Raymond T. Pierrehumbert , Roxana E. Lupu , John E. Moores

An admittedly pedantic but hopefully useful and informative analysis is presented of the EUVE 70--180 Angstrom spectra of nine polars. These spectra are fit with three different models---a blackbody, a pure-H stellar atmosphere, and a solar…

Astrophysics · Physics 2007-05-23 Christopher W. Mauche

Coronal loops are the basic structures of the solar transition region and corona. The understanding of physical mechanism behind the loop heating, plasma flows, and filling are still considered a major challenge in the solar physics. The…

Solar and Stellar Astrophysics · Physics 2015-02-24 G. R. Gupta , Durgesh Tripathi , Helen E. Mason

Accurate estimation of thermospheric density is critical for precise modeling of satellite drag forces in low Earth orbit (LEO). Improving this estimation is crucial to tasks such as state estimation, collision avoidance, and re-entry…

The aim of this work is to improve the modelling of ion populations in higher density, lower temperature astrophysical plasmas, of the type commonly found in lower solar and stellar atmospheres. Ion population models for these regions…

Solar and Stellar Astrophysics · Physics 2019-06-26 R. P. Dufresne , G. Del Zanna

Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from…

Solar and Stellar Astrophysics · Physics 2015-12-15 Judith de Patoul , Claire Foullon , Pete Riley

Magnetohydrodynamic waves are believed to play a significant role in coronal heating, and could be used for remote diagnostics of solar plasma. Both the heating and diagnostic applications rely on a correct inversion (or backward modelling)…

Solar and Stellar Astrophysics · Physics 2016-04-27 Ding Yuan , Tom Van Doorsselaere

Variations in the propagation of globally-propagating disturbances (commonly called "EIT waves") through the low solar corona offer a unique opportunity to probe the plasma parameters of the solar atmosphere. Here, high-cadence observations…

Solar and Stellar Astrophysics · Physics 2015-06-16 David M. Long , David R. Williams , Stéphane Régnier , Louise K. Harra

Photoevaporation caused by X-rays and ultraviolet radiation from the central star has attracted attention as a key process driving the dispersal of protoplanetary discs. Although numerous models have been used to investigate the…

Solar and Stellar Astrophysics · Physics 2025-04-07 Munehito Shoda , Riouhei Nakatani , Shinsuke Takasao