Analysis of the Fe X and Fe XIV line width in the solar corona using LASCO-C1 spectral data

Mierla, M.; Schwenn, R.; Teriaca, L.; Stenborg, G.; Podlipnik, B.

doi:10.1051/0004-6361:20078329

Cited by 32 publications

(32 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their spatial resolution is often too marginal for a deep spectroscopic analysis of barely resolved structures due to turbulent effects of the daytime seeing and inside the instrument where the solar disk is concentrated on the artificial Moon. In space, a similar difficulty occurs due to scattered light of instrumental origin (Mierla et al 2008). The F-component, which is superposed on the K-continuum, cannot be clearly detected from the interplanetary dust.…”

Section: Introductionmentioning

confidence: 99%

New deep coronal spectra from the 2017 total solar eclipse

Koutchmy

Baudin

Abdi

et al. 2019

A&A

View full text Add to dashboard Cite

Context. The origin of the high temperature of the solar corona, in both the inner bright parts and the more outer parts showing flows toward the solar wind, is not understood well yet. 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), and the dust component with F-lines (F-corona). Aims. By sufficiently dispersing the W-L spectrum, the Fraunhofer (F) spectrum of the dust component of the corona appears and the continuum Thomson radiation can be evaluated. The superposed emission lines of ions with different degrees of ionization are studied to allow the measurement of temperatures, non-thermal velocities, Doppler shifts, and abundances to constrain the proposed heating mechanisms and understand the origin of flows that lead to solar wind. Methods. We describe a slit spectroscopic experiment of high spectral resolution to provide an analysis of the most typical parts of the quasi-minimum type corona observed during the total solar eclipse of Aug 21, 2017 from Idaho, USA. Streamers, active region enhancements, and polar coronal holes (CHs) are measured well using deep spectra. Results. Sixty spectra are obtained during the totality with a long slit, covering ±3 solar radii in the range of 510 nm to 590 nm. The K+F continuum corona is exposed well up to two solar radii. The F-corona can be measured even at the solar limb. New weak emission lines were discovered or confirmed. The rarely observed Ar X line is detected almost everywhere; the Fe XIV and Ni XIII lines are clearly detected everywhere. For the first time hot lines are also measured inside the CH regions. The radial variations of the non-thermal turbulent velocities of the lines do not show a great departure from the average values. No significantly large Doppler shifts are seen anywhere in the inner or the middle corona. The wings of the Fe XIV line show some non-Gaussianity. Conclusions. Deep slit coronal spectra offered an opportunity for diagnosing several aspects of coronal physics during a well observed total eclipse without extended investments. The analysis of the ionic emission line profiles offers several powerful diagnostics of the coronal dynamics; the precise measurement of the F-continuum component provides insight into the ubiquitous dust corona at the solar limb.1

show abstract

Section: Introductionmentioning

confidence: 99%

New deep coronal spectra from the 2017 total solar eclipse

Koutchmy

Baudin

Abdi

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

“…Such signatures have been observed in situ in the solar wind (e.g. von Steiger et al, 1995, with the Ulysses spacecraft), and in the corona with remote-sensing methods and different instruments (with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer onboard the SOlar and Heliographic Observatory (SOHO) spacecraft: Tu et al (1998); the Large Angle and Spectrometric COronograph (LASCO) onboard SOHO: Mierla et al (2008); the UltraViolet Coronagraph Spectrometer (UVCS) onboard SOHO: Cranmer et al, 2008). One has to note, though, that anisotropies of temperature could also be produced by non-resonant Alfvén waves (Bourouaine et al, 2008a).…”

Section: Introductionmentioning

confidence: 99%

Solar off-limb line widths with SUMER: revised value of the non-thermal velocity and new results

Dolla

Solomon

2009

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Alfvén waves and ion-cyclotron absorption of high-frequency waves are frequently brought into models devoted to coronal heating and fast solar-wind acceleration. Signatures of ion-cyclotron resonance have already been observed in situ in the solar wind and in the upper corona. In the lower corona, one can use the line profiles to infer the ion temperatures. But the value of the so-called "non-thermal" (or "unresolved") velocity, potentially related to the amplitude of Alfvén waves propagating in the corona, is critical in firmly identifying ion-cyclotron preferential heating. In a previous paper, we proposed a method to constrain both the Alfvén wave amplitude and the preferential heating, above a polar coronal hole observed with the SUMER/SOHO spectrometer. Taking into account the effect of instrumental stray light before analysing the line profiles, we ruled out any direct evidence of damping of the Alfvén waves and showed that ions with the lowest charge-to-mass ratios were preferentially heated. We re-analyse these data here to correct the derived non-thermal velocity, and we discuss the consequences on the main results. We also include a measure of the FeVIII 1442.56Å line width (second order), thus extending the charge-to-mass ratio domain towards ions more likely to experience cyclotron resonance.

show abstract

“…The Alfven waves that propagate along open magnetic field lines may lead to a growth of a spectral line width with height [11,12,13,14,18]. However, at some altitudes the spectral line width reveals a sudden faU off [15,16,17].…”

Section: Discussionmentioning

confidence: 97%

“…The non-thermal broadening of coronal emission lines Mg X A6Q9 and 625, Fe XII /11242, O V A629, N V /11238 and 1242 was first observed by a rocket-borne instrument [11]. More recently it was found by the CDS and SUMER instruments on the SOHO spacecraft that the Doppler width generally increases with height [12,13,14,15,16,17,18]. This phenomenon was interpreted as a signature of outwardly propagating undamped Alfven waves.…”

Section: Non-thermal Broadening Of Solar Coronal Spectral Lines As a mentioning

confidence: 93%

“…As a result, contrary to magnetosonic waves, torsional Alfven waves can be observed only spectroscopically. While propagating from the base of the solar corona along open magnetic field lines, these waves may lead to an increase of a spectral line width with height [11,12,13,14,15,16,17,18]. In closed magnetic field structures, such as coronal loops, these waves can be observed indirectly as periodic variations of non-thermal broadening of spectral lines [19,20].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectral Line Non-thermal Broadening and MHD Waves in the Solar Corona

Zaqarashvili¹

2009

AIP Conference Proceedings

View full text Add to dashboard Cite

The rapid temperature rise from the solar surface (6 000 K) up to the corona (1 MK) and acceleration of solar wind particles still are unresolved problems in solar physics. The energy source for the coronal heating and the wind acceleration probably lies in the solar photosphere. MHD waves are believed to carry the photospheric energy into the corona. Recent observations from space based telescopes made significant progress in understanding the process of MHD wave propagation from the solar surface towards the corona. Some of MHD wave modes have been observed through intensity variations and Doppler shift oscillations in spectral lines. Another powerful mechanism is to detect the waves through the non-thermal broadening of spectral lines. The lecture gives the basic points of wave induced efi'ects in solar coronal spectral lines and recent progress in wave observations through spectral line non-thermal broadening.

show abstract

Analysis of the Fe X and Fe XIV line width in the solar corona using LASCO-C1 spectral data

Abstract: Aims. The purpose of this paper is to analyze the variation in the line width with height in the inner corona (region above 1

Cited by 32 publications

References 29 publications

New deep coronal spectra from the 2017 total solar eclipse

New deep coronal spectra from the 2017 total solar eclipse

Solar off-limb line widths with SUMER: revised value of the non-thermal velocity and new results

Spectral Line Non-thermal Broadening and MHD Waves in the Solar Corona

Contact Info

Product

Resources

About