Modeling of EIS Spectrum Drift from Instrumental Temperatures

Kamio, S.; Hara, Hirohisa; Watanabe, Tetsuya; Fredvik, T.; Hansteen, V. H.

doi:10.1007/s11207-010-9603-7

Cited by 81 publications

(97 citation statements)

References 16 publications

(15 reference statements)

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“…Next, missing pixels were interpolated, following the implementation of Young (2010) and using the eis_replace_missing.pro procedure. Systematic drifts in the wavelength scale were then taken into account using eis_shift_spec.pro, based on the empirical model of Kamio et al (2010). The four smaller rasters on 2007 March 13 were coaligned and averaged together in order to improve their statistical accuracy.…”

Section: Plume and Interplume Observationsmentioning

confidence: 99%

Relative Abundance Measurements in Plumes and Interplumes

Guennou

Hahn

Savin

2015

ApJ

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We present measurements of relative elemental abundances in plumes and interplumes. Plumes are bright, narrow structures in coronal holes that extend along open magnetic field lines far out into the corona. Previous work has found that in some coronal structures the abundances of elements with a low first ionization potential (FIP) <10 eV are enhanced relative to their photospheric abundances. This coronal-to-photospheric abundance ratio, commonly called the FIP bias, is typically 1 for elements with a high-FIP (>10 eV). We have used Extreme Ultraviolet Imaging Spectrometer observations made on 2007 March 13 and 14 over a ≈24 hr period to characterize abundance variations in plumes and interplumes. To assess their elemental composition, we used a differential emission measure analysis, which accounts for the thermal structure of the observed plasma. We used lines from ions of iron, silicon, and sulfur. From these we estimated the ratio of the iron and silicon FIP bias relative to that for sulfur. From the results, we have created FIP-bias-ratio maps. We find that the FIP-bias ratio is sometimes higher in plumes than in interplumes and that this enhancement can be time dependent. These results may help to identify whether plumes or interplumes contribute to the fast solar wind observed in situ and may also provide constraints on the formation and heating mechanisms of plumes.

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Section: Plume and Interplume Observationsmentioning

confidence: 99%

Relative Abundance Measurements in Plumes and Interplumes

Guennou

Hahn

Savin

2015

ApJ

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“…Additional corrections were made for coalignment between EIS's short wavelength (171-212Å) and long wavelength (250-290Å) bands (Young and Gallagher, 2008); instrument and orbital jitter variations (Shimizu et al, 2007); the sinusoidal spectrum drift of the lines on the CCD due to orbital changes , and the tilt of the emission lines on the detector. These corrections resulted in an absolute wavelength calibration of ± 4.4 km s −1 (Kamio et al, 2010). To investigate the magnetic structure of the events studied, we obtained closest-time data from the Michelson Dopper Imager (MDI; Scherrer et al, 1995) instrument onboard the SOHO satellite.…”

Section: Observationsmentioning

confidence: 99%

Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines

et al. 2013

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Since their discovery twenty year ago, transition region bright points have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we have investigated three transient quiet Sun brightenings including a transition region bright point (TR BP), a coronal bright point (CBP) and a blinker. We use time-series observations of the extreme ultraviolet emission lines of a wide range of temperature T (log T = 5.3 − 6.4) from the EUV imaging spectrometer (EIS) onboard the Hinode satellite. We present the EIS temperature maps and Doppler maps, which are compared with magnetograms from the Michelson Doppler Imager (MDI) onboard the SOHO satellite. Doppler velocities of the TR BP and blinker are ≤ 25 km s −1 , which is typical of transient TR phenomena. The Dopper velocities of the CBP were found to be ≤ 20 km s −1 with exception of those measured at log T = 6.2 where a distinct bi-directional jet is observed. From an EM loci analysis we find evidence of single and double isothermal components in the TR BP and CBP, respectively. TR BP and CBP loci curves are characterized by broad distributions suggesting the existence of unresolved structure. By comparing and contrasting the physical characteristics of the events we find the BP phenomena are an indication of multi-scaled self similarity, given similarities in both their underlying magnetic field configuration and evolution in relation to EUV flux changes. In contrast, the blinker phenomena and the TR BP are sufficiently dissimilar in their observed properties as to constitute different event classes. Our work is an indication that the measurement of similar characteristics across multiple event types holds class-predictive power, and is a significant step towards automated solar atmospheric multiclass classification of unresolved transient EUV sources. Finally, the analysis performed here establishes a connection between solar quiet region CBPs and jets.

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“…Venus' transit provides the ideal fiducial reference for measuring such errors since its silhouette must be seen at identical locations in each passband when the transit speed across the solar surface is accounted for (Kamio et al, 2010;Shimizu et al, 2007). Daily pointing variations from the various AIA passbands are determined from a direct comparison of the heliographic coordinates of Venus' center to those predicted by deriving the Venus' velocity using running difference images (1700Å passband; see Figure 4).…”

Section: Using the Venus Transit For Investigation Of Internal Aia Comentioning

confidence: 99%

Temporal Pointing Variations of the Solar Dynamics Observatory’s HMI and AIA Instruments on Subweekly Time Scales

et al. 2013

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Achieving sub-arcsecond co-registration across varying time-lines of multi-wavelength and instrument images is not trivial, and requires accurate characterization of instrument pointing jitter. In this work we have investigated internal pointing errors, on daily and yearly time-scales, occurring across the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) and Helioseismic Magnetic Imager (HMI). Using cross-correlation techniques on AIA 1700Å passband and HMI line-of-sight (LOS) magnetograms, from three years of observational image pairs at approximately three day intervals, internal pointing errors are quantified. Pointing variations of ± 0.26 (jitter limited) and ± 0.50 in the solar East-West (x) and North-South (y) directions, respectively, are measured. AIA observations of the Venus June 2012 transit are used to measure existing coalignment offsets in all passbands. We find AIA passband pointing variations are ∆X CO = 1.10 ± 1.41 and ∆Y CO = 1.25 ± 1.24 , when aligned to HMI's nominal image center, referred to herein as the CutOut technique (CO). Minimal long-term pointing variations found between limb and correlation derived pointings provide evidence that image center positions provided by the instrument teams achieve single pixel accuracy on time-scales below their characterization. However, daily AIA passband pointing variations of 1.18 indicate autonomous sub-arcsecond co-registration is not yet fully achievable.

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Modeling of EIS Spectrum Drift from Instrumental Temperatures

Cited by 81 publications

References 16 publications

Relative Abundance Measurements in Plumes and Interplumes

Relative Abundance Measurements in Plumes and Interplumes

Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines

Temporal Pointing Variations of the Solar Dynamics Observatory’s HMI and AIA Instruments on Subweekly Time Scales

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