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In this research, we investigate Explosive Events (EEs) in the off-limb solar atmosphere, with simultaneous observations from the Si IV, Mg II k, and slit-jaw images (SJI) of the Interface Region Imaging Spectrograph (IRIS), on 17 August…

Solar and Stellar Astrophysics · Physics 2022-07-06 E. Tavabi , S. Zeighami , M. Heydari

We present some new accurate CCD photometry analysis of the white light solar corona at the time of the last 20 March 2015 total eclipse (airborne observations on a Falcon 7X and at ground-based Svalbard). We measured coronal brightness…

Solar and Stellar Astrophysics · Physics 2015-10-23 C. Bazin , J. Vilinga , R. Wittich , S. Koutchmy , J. Mouette , C. Nitschelm

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

The inner regions of the solar corona from 1-2.5 Rsun are poorly sampled both from the ground and space telescopes. A solar eclipse reduces the sky scattered background intensity by a factor of about 10,000 and opens a window to view this…

Instrumentation and Methods for Astrophysics · Physics 2016-12-21 M J Penn , R Baer , R Bosh , D Garrison , R Gelderman , H Hare , F Isberner , L Jensen , S Kovac , M McKay , A Mitchell , M Pierce , A Ursache , J Varsik , D Walter , Z Watson , D Young , the Citizen CATE Team

We present a new method that combines the results of an oscillation study made in optical and radio observations. The optical spectral measurements in photospheric and chromospheric lines of the line-of-sight velocity were carried out at…

Solar and Stellar Astrophysics · Physics 2015-03-18 V. E. Abramov-Maximov , G. B. Gelfreikh , N. I. Kobanov , K. Shibasaki , S. A. Chupin

New calculations of radiative rates and electron impact excitation cross sections for Fe XI are used to derive emission line intensity ratios involving 3s^23p^4 - 3s^23p^33d transitions in the 180-223 A wavelength range. These ratios are…

Solar eclipse is an unique opportunity to study the lower ionospheric variabilities under a controlled perturbation when the solar ultraviolet and X-ray are temporally occulted by the lunar disk. Sub-ionospheric Very Low Frequency (VLF)…

Earth and Planetary Astrophysics · Physics 2018-07-04 Sandip K. Chakrabarti , Sudipta Sasmal , Tamal Basak , Suman Chakraborty , Robert L. Tucker

Analysis of the solar coronal green line profiles reveals information regarding the physical conditions of the solar corona like temperature, density, Doppler velocity, non-thermal velocity etc. It provides insights to the unresolved…

Solar and Stellar Astrophysics · Physics 2013-07-02 Maya Prabhakar , K. P. Raju , T. Chandrasekhar

Aims. We study the coherency of solar spicules intensity oscillations with increasing height above the solar limb in quiet Sun, active Sun and active region using observations from HINODE/SOT. Existence of coherency up to transition region…

Solar and Stellar Astrophysics · Physics 2015-07-15 E. Tavabi , A. Ajabshirizadeh , A. R. Ahangarzadeh Maralani , S. Zeighami

We report Doppler measurements of alpha Cen A from time-series spectroscopy made with UCLES at the 3.9-m AAT. Wavelength calibration using an iodine absorption cell produced high-precision velocity measurements, whose power spectrum shows…

Observations of a large solar flare of December 13, 2006, using Solar Optical Telescope (SOT) on Hinode spacecraft revealed high-frequency oscillations excited by the flare in the sunspot chromosphere. These oscillations are observed in the…

Astrophysics · Physics 2009-11-13 A. G. Kosovichev , T. Sekii

This paper presents an overview of results obtained during the CAWSES II period on the short term variability of the Sun and how it affects the near Earth space environment. CAWSES II was planned to examine the behavior of the solar…

Solar and Stellar Astrophysics · Physics 2015-04-27 Nat Gopalswamy , Bruce Tsurutani , Yihua Yan

We describe microwave and hard X-ray observations of strong quasiperiodic pulsations from the GOES X1.3 solar flare on 15 June 2003. The radio observations were made jointly by the Owens Valley Solar Array (OVSA), the Nobeyama Polarimeter…

Astrophysics · Physics 2009-11-13 G. D. Fleishman , T. S. Bastian , D. E. Gary

We report the results of polarimetric observations of the total solar eclipse of 21 August 2017 from Rexburg, Idaho (USA). We use three synchronized DSLR cameras with polarization filters oriented at 0{\deg}, 60{\deg}, and 120{\deg} to…

Total eclipses permit a deep analysis of both the inner and the outer parts of the corona using the continuum White-Light (W-L) radiations from electrons (K-corona), the superposed spectrum of forbidden emission lines from ions (E-corona)…

Solar and Stellar Astrophysics · Physics 2019-12-11 S. Koutchmy , F. Baudin , Sh. Abdi , L. Golub , F. Sèvre

High-frequency wave phenomena present a great deal of interest as one of the possible candidates to contribute to the energy input required to heat the corona as a part of the AC heating theory. However, the resolution of imaging…

Solar and Stellar Astrophysics · Physics 2023-04-05 Elena Petrova , Norbert Magyar , Tom Van Doorsselaere , David Berghmans

We introduce WECS (Wavelet Energies Correlation Sreening), an unsupervised sparse procedure to detect spatio-temporal change points on multi-temporal SAR (POLSAR) images or even on sequences of very high resolution images. The procedure is…

Applications · Statistics 2021-03-29 Rodney Fonseca , Aluísio Pinheiro , Abdourrahmane Atto

Context: The origin of the variable component of the solar wind is of great intrinsic interest for heliophysics and space-weather, e.g. the initiation of coronal mass ejections, and the problem of mass loss of all stars. It is also related…

Solar and Stellar Astrophysics · Physics 2015-05-28 K. Bocchialini , F. Baudin , S. Koutchmy , G. Pouget , J. Solomon

The Mars Global Surveyor (MGS), Mars Express (MEX), and Venus Express (VEX) experienced several superior solar conjunctions. These conjunctions cause severe degradations of radio signals when the line of sight between the Earth and the…

Space Physics · Physics 2013-01-08 A. K. Verma , A. Fienga , J. Laskar , K. Issautier , H. Manche , M. Gastineau

A high-speed halo-type coronal mass ejection (CME), associated with a GOES M4.6 soft X-ray flare in NOAA AR 0180 at S12W29 and an EIT wave and dimming, occurred on 9 November 2002. A complex radio event was observed during the same period.…