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 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.

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 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 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.

scholarly journals Energetics of magnetic transients in a solar active region plage

2019 ◽  
Vol 623 ◽  
pp. A176 ◽  
Author(s):  
L. P. Chitta ◽  
A. R. C. Sukarmadji ◽  
L. Rouppe van der Voort ◽  
H. Peter
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Magnetic Flux ◽  
Numerical Simulations ◽  
Extreme Ultraviolet ◽  
Spatial Scales ◽  
Coronal Loops ◽  
The Sun ◽  
Flux Emergence ◽  
Transient Events

Context. Densely packed coronal loops are rooted in photospheric plages in the vicinity of active regions on the Sun. The photospheric magnetic features underlying these plage areas are patches of mostly unidirectional magnetic field extending several arcsec on the solar surface. Aims. We aim to explore the transient nature of the magnetic field, its mixed-polarity characteristics, and the associated energetics in the active region plage using high spatial resolution observations and numerical simulations. Methods. We used photospheric Fe I 6173 Å spectropolarimetric observations of a decaying active region obtained from the Swedish 1-m Solar Telescope (SST). These data were inverted to retrieve the photospheric magnetic field underlying the plage as identified in the extreme-ultraviolet emission maps obtained from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). To obtain better insight into the evolution of extended unidirectional magnetic field patches on the Sun, we performed 3D radiation magnetohydrodynamic simulations of magnetoconvection using the MURaM code. Results. The observations show transient magnetic flux emergence and cancellation events within the extended predominantly unipolar patch on timescales of a few 100 s and on spatial scales comparable to granules. These transient events occur at the footpoints of active region plage loops. In one case the coronal response at the footpoints of these loops is clearly associated with the underlying transient. The numerical simulations also reveal similar magnetic flux emergence and cancellation events that extend to even smaller spatial and temporal scales. Individual simulated transient events transfer an energy flux in excess of 1 MW m−2 through the photosphere. Conclusions. We suggest that the magnetic transients could play an important role in the energetics of active region plage. Both in observations and simulations, the opposite-polarity magnetic field brought up by transient flux emergence cancels with the surrounding plage field. Magnetic reconnection associated with such transient events likely conduits magnetic energy to power the overlying chromosphere and coronal loops.

scholarly journals Coherence tomography with broad bandwidth extreme ultraviolet and soft X-ray radiation

2021 ◽  
Vol 127 (4) ◽  
Author(s):  
S. Skruszewicz ◽  
S. Fuchs ◽  
J. J. Abel ◽  
J. Nathanael ◽  
J. Reinhard ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Near Infrared ◽  
Extreme Ultraviolet ◽  
Infrared Light ◽  
Imaging Method ◽  
Optical Coherence ◽  
Axial Resolution ◽  
Cross Sectional ◽  
X Ray ◽  
Broad Bandwidth

AbstractWe present an overview of recent results on optical coherence tomography with the use of extreme ultraviolet and soft X-ray radiation (XCT). XCT is a cross-sectional imaging method that has emerged as a derivative of optical coherence tomography (OCT). In contrast to OCT, which typically uses near-infrared light, XCT utilizes broad bandwidth extreme ultraviolet (XUV) and soft X-ray (SXR) radiation (Fuchs et al in Sci Rep 6:20658, 2016). As in OCT, XCT’s axial resolution only scales with the coherence length of the light source. Thus, an axial resolution down to the nanometer range can be achieved. This is an improvement of up to three orders of magnitude in comparison to OCT. XCT measures the reflected spectrum in a common-path interferometric setup to retrieve the axial structure of nanometer-sized samples. The technique has been demonstrated with broad bandwidth XUV/SXR radiation from synchrotron facilities and recently with compact laboratory-based laser-driven sources. Axial resolutions down to 2.2 nm have been achieved experimentally. XCT has potential applications in three-dimensional imaging of silicon-based semiconductors, lithography masks, and layered structures like XUV mirrors and solar cells.

scholarly journals Table-top extreme ultraviolet second harmonic generation

2021 ◽  
Vol 7 (21) ◽  
pp. eabe2265
Author(s):  
Tobias Helk ◽  
Emma Berger ◽  
Sasawat Jamnuch ◽  
Lars Hoffmann ◽  
Adeline Kabacinski ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
First Principles ◽  
Extreme Ultraviolet ◽  
Second Harmonic ◽  
High Harmonic ◽  
Electronic Structure Calculations ◽  
Free Electron Lasers ◽  
X Ray ◽  
Structure Calculations

The lack of available table-top extreme ultraviolet (XUV) sources with high enough fluxes and coherence properties has limited the availability of nonlinear XUV and x-ray spectroscopies to free-electron lasers (FELs). Here, we demonstrate second harmonic generation (SHG) on a table-top XUV source by observing SHG near the Ti M2,3 edge with a high-harmonic seeded soft x-ray laser. Furthermore, this experiment represents the first SHG experiment in the XUV. First-principles electronic structure calculations suggest the surface specificity and separate the observed signal into its resonant and nonresonant contributions. The realization of XUV-SHG on a table-top source opens up more accessible opportunities for the study of element-specific dynamics in multicomponent systems where surface, interfacial, and bulk-phase asymmetries play a driving role.

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