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Related papers: Estimating Electron Densities in the Middle Solar …

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We present coronal density profiles derived from low-frequency (80-240 MHz) imaging of three type III solar radio bursts observed at the limb by the Murchison Widefield Array (MWA). Each event is associated with a white light streamer at…

Solar and Stellar Astrophysics · Physics 2018-10-17 Patrick I. McCauley , Iver H. Cairns , John Morgan

Accurate measurements of electron density are critical for determination of the plasma properties in the solar corona. We compare the electron densities diagnosed from Fe XIII lines observed by the Extreme-Ultraviolet Imaging Spectrometer…

Context: The sharp temperature and density gradients in the coronal transition region are a challenge for models and observations. Aims: We set out to get linearly- and quadratically-weighted average electron densities in the region…

Solar and Stellar Astrophysics · Physics 2015-05-13 E. Buchlin , J. -C. Vial

Tomography of the solar corona can provide cruicial constraints for models of the low corona, unique information on changes in coronal structure and rotation rates, and a valuable boundary condition for models of the heliospheric solar…

Instrumentation and Methods for Astrophysics · Physics 2015-09-11 Huw Morgan

The total solar eclipse of August 21st, 2017 was observed with a Digital Single Lens Reflex (DSLR) camera equipped with a linear polarizing filter. A method was developed to combine images acquired with 15 different exposure times (from…

Solar and Stellar Astrophysics · Physics 2020-12-09 Alessandro Bemporad

Determining the electron density is a challenging task in solar corona studies, as it requires certain assumptions to be made, such as symmetric, homogeneous and radial distribution, thermal equilibrium, etc. In such studies, the observed…

Solar and Stellar Astrophysics · Physics 2023-10-24 Hikmet Çakmak

The quiet solar corona emits meter-wave thermal bremsstrahlung. Coronal radio emission can only propagate above that radius, $R_\omega$, where the local plasma frequency eqals the observing frequency. The radio interferometer LOw Frequency…

Solar and Stellar Astrophysics · Physics 2018-06-13 C. Vocks , G. Mann , F. Breitling , M. M. Bisi , B. Dabrowski , R. Fallows , P. T. Gallagher , A. Krankowski , J. Magdalenic , C. Marque , D. Morosan , H. Rucker

The Sun's corona has interested researchers for multiple reasons, including the search for solution for the famous coronal heating problem and a purely practical consideration of predicting geomagnetic storms on Earth. There exist numerous…

Solar and Stellar Astrophysics · Physics 2019-11-13 Dan Aksim , Alexey Melnikov , Dmitry Pavlov , Sergey Kurdubov

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

Three dimensional electron density distributions in the solar corona are reconstructed for 100 Carrington Rotations (CR 2054$-$2153) during 2007/03$-$2014/08 using the spherically symmetric method from polarized white-light observations…

Solar and Stellar Astrophysics · Physics 2017-07-25 Tongjiang Wang , Nelson L. Reginald , Joseph M. Davila , O. Chris St. Cyr , William T. Thompson

Understanding the density structure of the solar corona is important for modeling both coronal heating and the solar wind. Direct measurements are difficult because of line-of-sight integration and possible unresolved structures. We present…

Solar and Stellar Astrophysics · Physics 2016-09-28 Michael Hahn , Daniel Wolf Savin

The distribution of the coronal electron density at different distances from the Sun strongly influences the physical processes in the solar corona and is therefore a very important topic in solar physics. Most methods, including radio…

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…

We present spectropolarimetric imaging observations of the solar corona at low frequencies (80 - 240 MHz) using the Murchison Widefield Array (MWA). These images are the first of their kind, and we introduce an algorithm to mitigate an…

Solar and Stellar Astrophysics · Physics 2019-09-04 Patrick I. McCauley , Iver H. Cairns , Stephen M. White , Surajit Mondal , Emil Lenc , John Morgan , Divya Oberoi

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

We present an analysis of deep $\textit{JWST}$/NIRSpec spectra of star-forming galaxies at $z\simeq1.4-10$, observed as part of the AURORA survey. We infer median low-ionization electron densities of $268_{-49}^{+45}~\rm cm^{-3}$,…

Low-frequency (80-240 MHz) radio observations of the solar corona are presented using the Murchison Widefield Array (MWA), and several discoveries are reported. The corona is reviewed, followed by chapters on Type III bursts and…

Solar and Stellar Astrophysics · Physics 2019-12-05 Patrick I. McCauley

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

Measurements of the temperature and density structure of the solar corona provide critical constraints on theories of coronal heating. Unfortunately, the complexity of the solar atmosphere, observational uncertainties, and the limitations…

Solar and Stellar Astrophysics · Physics 2009-07-22 Harry P. Warren , David H. Brooks

We use very precise frequencies of low-degree solar-oscillation modes measured from 4752 days of data collected by the Birmingham Solar-Oscillations Network (BiSON) to derive seismic information on the solar core. We compare these…

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