10. X-Ray and Extreme Ultraviolet Observations of the Sun

1979 ◽  
pp. 56-61
Keyword(s):  
Extreme Ultraviolet ◽  
The Sun ◽  
X Ray ◽  
Ultraviolet Observations

scholarly journals Ultraviolet Observations of Stellar Coronae: Early Results from HST

1992 ◽  
Vol 9 ◽  
pp. 657-658
Author(s):  
J.L. Linsky
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Solar Flares ◽  
Extreme Ultraviolet ◽  
The Sun ◽  
X Ray ◽  
Spectroscopic Diagnostics ◽  
Early Results ◽  
Active Stars ◽  
Ultraviolet Observations

Although coronae for stars other than the Sun have previously been detected only in the X-ray and radio portions of the spectrum, the HST and future spacecraft sensitive to ultraviolet (UV) and extreme ultraviolet (ETIV) light will have the spectral resolution to study the dynamics and spectroscopic diagnostics of hot coronal plasmas. In the UV region accessible to HST, forbidden lines of FeXII at 1242 and 1349Å, of FeXXI at 1354Å, and other species seen in solar flares, are predicted to be present in the spectra of active stars. Upcoming observations with the Goddard High Resolution Spectrograph (GHRS) by S. Maran will search for these lines in the dM2e star AU Mic and other stars.

scholarly journals Hot prominence spicules launched from turbulent cool solar prominences

2019 ◽  
Vol 627 ◽  
pp. L5 ◽  
Author(s):  
L. P. Chitta ◽  
H. Peter ◽  
L. Li
Keyword(s):  
Transition Region ◽  
Extreme Ultraviolet ◽  
The Sun ◽  
Solar Dynamics Observatory ◽  
Solar Prominences ◽  
Solar Filament ◽  
Solar Dynamics ◽  
Ultraviolet Observations ◽  
Hot Corona ◽  
Shed Light

A solar filament is a dense cool condensation that is supported and thermally insulated by magnetic fields in the rarefied hot corona. Its evolution and stability, leading to either an eruption or disappearance, depend on its coupling with the surrounding hot corona through a thin transition region, where the temperature steeply rises. However, the heating and dynamics of this transition region remain elusive. We report extreme-ultraviolet observations of quiescent filaments from the Solar Dynamics Observatory that reveal prominence spicules propagating through the transition region of the filament-corona system. These thin needle-like jet features are generated and heated to at least 0.7 MK by turbulent motions of the material in the filament. We suggest that the prominence spicules continuously channel the heated mass into the corona and aid in the filament evaporation and decay. Our results shed light on the turbulence-driven heating in magnetized condensations that are commonly observed on the Sun and in the interstellar medium.

scholarly journals Extreme ultraviolet observations of active regions in the solar corona

1968 ◽  
Vol 35 ◽  
pp. 395-402
Author(s):  
W. M. Burton
Keyword(s):  
High Temperature ◽  
Extreme Ultraviolet ◽  
Active Regions ◽  
Pinhole Camera ◽  
Emission Region ◽  
The Sun ◽  
Coronal Emission ◽  
Improved Design ◽  
Ultraviolet Observations ◽  
Plane Diffraction

The coronal features associated with solar active regions can be observed by recording images of the Sun at extreme ultraviolet (XUV) wavelengths. Pinhole cameras have been flown on stabilized sun-pointing ‘Skylark’ rockets to obtain broad-waveband XUV solar images. These images show localised emission from high-temperature regions located in the corona above calcium-plage areas. An improved design of pinhole camera, which uses a plane-diffraction grating to give increased spectral resolution, has recorded spectroheliograms in several intense solar lines including He II (304 Å), Fe IX–XI (180 Å), and Si X–XII (50 Å). Estimates are made of the size and brightness of the coronal emission region associated with a developing calcium-plage area.

scholarly journals Future Prospects for Solar EUV and Soft X-Ray Spectroscopy Missions

2021 ◽  
Vol 8 ◽  
Author(s):  
Peter R. Young
Keyword(s):  
Extreme Ultraviolet ◽  
Imaging Techniques ◽  
Low Cost ◽  
Solar Physics ◽  
Spectral Features ◽  
The Sun ◽  
Future Prospects ◽  
X Ray

Future prospects for solar spectroscopy missions operating in the extreme ultraviolet (EUV) and soft X-ray (SXR) wavelength ranges, 1.2–1,600 Å, are discussed. NASA is the major funder of Solar Physics missions, and brief summaries of the opportunities for mission development under NASA are given. Upcoming major solar missions from other nations are also described. The methods of observing the Sun in the two wavelength ranges are summarized with a discussion of spectrometer types, imaging techniques and detector options. The major spectral features in the EUV and SXR regions are identified, and then the upcoming instruments and concepts are summarized. The instruments range from large spectrometers on dedicated missions, to tiny, low-cost CubeSats launched through rideshare opportunities.

X-ray and extreme ultraviolet (1?400 �) spectroscopy of the sun, from OSO-III

Solar Physics ◽  
1969 ◽  
Vol 6 (2) ◽  
pp. 183-192 ◽  
Author(s):  
W. M. Neupert ◽  
W. A. White ◽  
W. J. Gates ◽  
M. Swartz ◽  
R. M. Young
Keyword(s):  
Extreme Ultraviolet ◽  
The Sun ◽  
X Ray

scholarly journals Dynamical Effects in the EUV Chromospheric Network

1977 ◽  
Vol 43 ◽  
pp. 10-10
Author(s):  
F.G. Chiuderi-Drago ◽  
G. Poletto
Keyword(s):  
Extreme Ultraviolet ◽  
Network Models ◽  
Average Intensity ◽  
The Sun ◽  
Harvard College ◽  
Spatial Intensity Distribution ◽  
Euv Emission ◽  
Chromospheric Network ◽  
Harvard College Observatory ◽  
Ultraviolet Observations

Extreme ultraviolet observations of the chromospheric network obtained by the Harvard College Observatory experiment aboard Skylab on May 31st, 1973, are analyzed.The data, which have a spatial resolution of 5“ x 5“, cover an area of 5‘ x 5‘ near the center of the sun, where a large coronal hole was present, and are recorded in several lines formed in a range of temperatures from 104 to 106 °K.By studying the EUV spatial intensity distribution, the average intensity in cell and network, the contrast, and the emission measures have been derived.The network distribution, highly asymmetrical and skewed to higher intensity, suggests an inhomogeneous network structure, probably associated with the presence of spicules, not resolved by the instrument.A dynamical model of the transition zone is therefore developed, and the resulting EUV emission in spicules is computed and compared with available observations, and with previous network models.

scholarly journals Glancing Incidence Optics for X-Ray and Ultraviolet Astronomy

1971 ◽  
Vol 41 ◽  
pp. 192-204 ◽  
Author(s):  
J. H. Underwood ◽  
W. M. Neupert ◽  
R. B. Hoover
Keyword(s):  
Spatial Resolution ◽  
Extreme Ultraviolet ◽  
Laboratory Data ◽  
Spectral Lines ◽  
The Sun ◽  
Ultraviolet Astronomy ◽  
X Ray ◽  
High Resolution Images

Glancing incidence telescopes of the kind first described by Wolter have now been physically realized, so that it is now possible to obtain high resolution images of celestial objects at all wavelengths greater than about 3 Å. In this paper we shall describe two such instruments: the GSFC-MSFC X-ray telescope for the Apollo telescope mount uses Wolter type 1 optics and is capable of forming images of the sun in the 8–70 Å region with spatial resolution of the order of one arc second. The GSFC extreme ultraviolet spectroheliometer for OSO H uses type 2 optics and can obtain images of the Sun in spectral lines in the 170–400 Å region with a spatial resolution of about ten arc seconds. Theoretical (ray trace) and laboratory data on these systems will be presented.

scholarly journals Radio, X-Ray, and Extreme-ultraviolet Observations of Weak Energy Releases in the “Quiet” Sun

2021 ◽  
Vol 918 (1) ◽  
pp. L18
Author(s):  
R. Ramesh ◽  
C. Kathiravan ◽  
N. P. S. Mithun ◽  
S. V. Vadawale
Keyword(s):  
Extreme Ultraviolet ◽  
X Ray ◽  
Quiet Sun ◽  
Ultraviolet Observations

scholarly journals Solar extreme ultraviolet (EUV) flare observations and findings from the Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE)

2015 ◽  
Vol 11 (S320) ◽  
pp. 27-40
Author(s):  
Thomas N. Woods ◽  
Francis G. Eparvier ◽  
James P. Mason
Keyword(s):  
Extreme Ultraviolet ◽  
Late Phase ◽  
Impulsive Phase ◽  
The Sun ◽  
Solar Dynamics Observatory ◽  
X Ray ◽  
Gradual Phase ◽  
Stellar Flares ◽  
Solar Dynamics ◽  
Coronal Dimming

AbstractNew solar soft X-ray (SXR) and extreme ultraviolet (EUV) irradiance observations from NASA Solar Dynamics Observatory (SDO) EUV Variability Experiment (EVE) provide full coverage from 0.1 to 106 nm and continuously at a cadence of 10 seconds for spectra at 0.1 nm resolution. These observations during flares can usually be decomposed into four distinct characteristics: impulsive phase, gradual phase, coronal dimming, and EUV late phase. Over 6000 flares have been observed during the SDO mission; some flares show all four phases, and some only show the gradual phase. The focus is on the newer results about the EUV late phase and coronal dimming and its relationship to coronal mass ejections (CMEs). These EVE flare measurements are based on observing the sun-as-a-star, so these results could exemplify stellar flares. Of particular interest is that new coronal dimming measurements of stars could be used to estimate mass and velocity of stellar CMEs.

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