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Maltby, P.; Brynildsen, N.; Fredvik, T.; Kjeldseth-Moe, O.; Wilhelm, K.

doi:10.1023/a:1005242405179

Cited by 39 publications

(36 citation statements)

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“…In sunspot plumes, considerable downflows have been reported (see e.g. Maltby et al 1999;Brynildsen et al 2001;Brosius & Landi 2005) and also for the sunspot plume in our raster images, downflows are observd ( +40 km s −1 ). Thus, it could be possible that the restructuring of the magnetic field in the microflare enhances the downflows in the plume.…”

Section: Discussionsupporting

confidence: 67%

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Multi-wavelength fine structure and mass flows in solar microflares

Berkebile-Stoiser¹,

Gömöry

Veronig³

et al. 2009

A&A

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Section: Discussionsupporting

confidence: 67%

“…Thus, bright features like sunspot plumes and their associated flows do not influence the wavelength calibration (see e.g. Maltby et al 1999). The thus obtained mean profile was supposed to be unshifted, i.e.…”

Section: Space-borne Instrumentsmentioning

confidence: 94%

Multi-wavelength fine structure and mass flows in solar microflares

Berkebile-Stoiser¹,

Gömöry

Veronig³

et al. 2009

A&A

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“…Maltby et al (1999) also find that the entire umbral transition region oscillates. However, the transition region above a sunspot can be highly non-uniform, particularly at temperatures 1.5 − 4 10 5 K, where one can see so called sunspot plumes, i.e., prominent features in the transition region above sunspots (Foukal et al 1974;Foukal 1976), first seen in the CDS data as very bright features in the O V 629.7Å line (peak formation at 2.2 10 5 K) by Fludra et al (1997) and described in detail by Brynildsen et al (1999b).…”

Section: Introductionmentioning

confidence: 74%

Transition region oscillations above sunspots

Fludra

2001

A&A

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Abstract. We present observations of three sunspots made in the EUV wavelength range with the Coronal Diagnostic Spectrometer (CDS) on SOHO. We examine time series of line intensities obtained with a 15-s cadence and calculate their Fourier power spectra and the wavelet transforms. We find oscillations in the chromosphere and transition region above sunspots in the temperature range 2 10 4 -4 10 5 K. Most of the spectral power is contained in the 5-8 mHz frequency range, and the dominant frequency is 5.9 mHz (170 s period). We find a relationship between the oscillations and sunspot plumes which are compact features located above sunspots and bright in the transition region lines emitted between 1.7 10 5 and 4 10 5 K. When the CDS slit crosses a sunspot plume, the bright O IV 554.5Å and O V 629.7Å lines show clear 3 min oscillations. An extreme alternative interpretation that excludes the presence of oscillations in sunspot plumes carries the requirement that the adjacent low-intensity plasma oscillate with high relative amplitudes greater than 50 percent. We also observe oscillations in a fainter area above a sunspot, outside the sunspot plume. The oscillations seen at different temperatures are compared. Using the wavelet transform, we find variability of the oscillation period in the range 120-200 s.

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“…This might be interpreted as a coronal funnel, the cool emission indicating the location of its footpoint, but further analysis of magnetic data would be needed for a conclusion on this. Even though not emerging from a full sunspot, this structure might also be related to a sunspot plume (Maltby et al 1999) because the emission from Fe x shows a redshift associated with it (cf. Fig.…”

Section: Solar Wind Outflow From Filamentary Funnels?mentioning

confidence: 99%

Asymmetries of solar coronal extreme ultraviolet emission lines

Peter¹

2010

A&A

117

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Context. The profiles of emission lines formed in the corona contain information on the dynamics and the heating of the hot plasma. Only recently has data with sufficiently high spectral resolution become available for investigating the details of the profiles of emission lines formed well above 10 6 K. These show enhanced emission in the line wings, which has not been understood yet. Aims. We study the underlying processes leading to asymmetric line profiles, in particular the responsible plasma flows and line broadening mechanisms in a highly filamentary and dynamic atmosphere.Methods. Line profiles of Fe xv formed at 2.5 MK acquired by the Extreme ultraviolet Imaging Spectrometer (EIS) onboard the Hinode solar space observatory are studied using multi Gaussian fits, with emphasis on the resulting line widths and Doppler shifts. Results. In the major part of the active region, the spectra are best fit by a narrow line core and a broad minor component. The latter contributes some 10% to 20% to the total emission, is about a factor of 2 broader than the core, and shows strong blueshifts of up to 50 km s −1 , especially in the footpoint regions of the loops. On average, the line width increases from the footpoints to the loop top for both components. A component with high upflow speeds can be found also in small restricted areas. Conclusions. The coronal structures consist of at least two classes that are not resolved spatially but only spectroscopically and that are associated with the line core and the minor component. Because of their huge line width and strong upflows, it is proposed that the major part of the heating and the mass supply to the corona is actually located in source regions of the minor component. It might be that these are identical to type II spicules. The siphon flows and draining loops seen in the line core component are consistent with structures found in a three-dimensional magneto-hydrodynamic (3D MHD) coronal model. Despite the quite different appearance of the large active region corona and small network elements seen in transition region lines, both show similar line profile characteristics. This indicates that the same processes govern the heating and dynamics of the transition region and the corona.

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Cited by 39 publications

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Multi-wavelength fine structure and mass flows in solar microflares

Multi-wavelength fine structure and mass flows in solar microflares

Transition region oscillations above sunspots

Asymmetries of solar coronal extreme ultraviolet emission lines

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