Imaging Spectroscopy of a White-Light Solar Flare

Oliveros, J. C. Martinez; Couvidat, S.; Schou, J.; Krucker, S.; Lindsey, C.; Hudson, H. S.; Scherrer, P. H.

doi:10.1007/s11207-010-9696-z

Cited by 38 publications

(34 citation statements)

References 30 publications

(38 reference statements)

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“…The acceleration of electrons outward to relativistic speeds generating radio emission is linked to the hard X-ray emission from the inward-penetrating electrons. Investigations of white light flares in spectral lines and continuum bands with multiple satellites demonstrate their temporal and spatial coherence with hard X-ray emission (Martínez Oliveros et al 2011;Watanabe et al 2013). This supports the case of white light emission occurring primarily during the IP.…”

Section: Introductionsupporting

confidence: 59%

Measurements and Modeling of Total Solar Irradiance in X-Class Solar Flares

Moore

Chamberlin

Hock

2014

ApJ

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The Total Irradiance Monitor (TIM) from NASA's SOlar Radiation and Climate Experiment can detect changes in the total solar irradiance (TSI) to a precision of 2 ppm, allowing observations of variations due to the largest X-class solar flares for the first time. Presented here is a robust algorithm for determining the radiative output in the TIM TSI measurements, in both the impulsive and gradual phases, for the four solar flares presented in Woods et al., as well as an additional flare measured on 2006 December 6. The radiative outputs for both phases of these five flares are then compared to the vacuum ultraviolet (VUV) irradiance output from the Flare Irradiance Spectral Model (FISM) in order to derive an empirical relationship between the FISM VUV model and the TIM TSI data output to estimate the TSI radiative output for eight other X-class flares. This model provides the basis for the bolometric energy estimates for the solar flares analyzed in the Emslie et al. study.

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Section: Introductionsupporting

confidence: 59%

Measurements and Modeling of Total Solar Irradiance in X-Class Solar Flares

Moore

Chamberlin

Hock

2014

ApJ

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“…In the case discussed by Martínez Oliveros et al [], HMI data showed spurious blue shifts of the Fe line. In addition, temporal interpolation involving negative coefficients in adjacent 45 s intervals can result in spurious “black‐light” flares [ Martínez Oliveros et al , ]. These factors complicate the interpretation of the HMI white‐light continuum images and presumably introduce a large uncertainty in the corresponding white‐light fluxes.…”

Section: Discussionmentioning

confidence: 99%

Bright 30 THz impulsive solar bursts

et al. 2015

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Impulsive 30 THz continuum bursts have been recently observed in solar flares, utilizing small telescopes with a unique and relatively simple optical setup concept. The most intense burst was observed together with a GOES X2 class event on 27 October 2014, also detected at two subterahertz (sub‐THz) frequencies, Reuven Ramaty High Energy Solar Spectroscopic Imager X‐rays and Solar Dynamics Observatory/Helioseismic and Magnetic Imager and EUV. It exhibits strikingly good correlation in time and in space with white‐light flare emission. It is likely that this association may prove to be very common. All three 30 THz events recently observed exhibited intense fluxes in the range of 104 solar flux units, considerably larger than those measured for the same events at microwave and submillimeter wavelengths. The 30 THz burst emission might be part of the same spectral burst component found at sub‐THz frequencies. The 30 THz solar bursts open a promising new window for the study of flares at their origin.

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“…For a given wavelength/polarization pair, the temporal interpolation ordinarily requires six Level-1 filtergrams in definitive mode and two in NRT mode to interpolate to the requested time. The two-point NRT temporal interpolation is a basic linear scheme, while the definitive six-point method uses the specific weighting scheme described in Martínez Oliveros et al (2011). When the loop over all wavelengths and polarizations is complete, the result is a set of filtergrams with the same solar radius and Sun-center position all interpolated to the proper observable time: T_OBS at the spacecraft.…”

Section: Filtergram Selection Mapping and Image Processingmentioning

confidence: 99%

Observables Processing for the Helioseismic and Magnetic Imager Instrument on the Solar Dynamics Observatory

et al. 2016

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NASA's Solar Dynamics Observatory (SDO) spacecraft was launched 11 February 2010 with three instruments onboard, including the Helioseismic and Magnetic Imager (HMI). After commissioning, HMI began normal operations on 1 May 2010 and has subsequently observed the Sun's entire visible disk almost continuously. HMI collects sequences of polarized filtergrams taken at a fixed cadence with two 4096 × 4096 cameras, from which are computed arcsecond-resolution maps of photospheric observables that include line-ofsight velocity and magnetic field, continuum intensity, line width, line depth, and the Stokes polarization parameters [I, Q, U, V ]. Two processing pipelines have been implemented at the SDO Joint Science Operations Center (JSOC) at Stanford University to compute these observables from calibrated Level-1 filtergrams, one that computes line-of-sight quantities every 45 seconds and the other, primarily for the vector magnetic field, that computes averages on a 720-second cadence. Corrections are made for static and temporally changing CCD characteristics, bad pixels, image alignment and distortion, polarization irregularities, filter-element uncertainty and nonuniformity, as well as Sun-spacecraft velocity. We detail the functioning of these two pipelines, explain known issues affecting the measurements of the resulting physical quantities, and describe how regular updates to the instrument calibration impact them. We also describe how the scheme for computing the observables is optimized for actual HMI observations. Initial calibration of HMI was performed on the ground using a variety of light sources and calibration sequences. During the five years of the SDO prime mission, regular calibration sequences have been taken on orbit to improve and regularly update the instrument calibration, and to monitor changes in the HMI instrument. This has resulted in several changes in the observables processing that are detailed here. The instrument more than satisfies all of the original specifications for data quality and continuity. The procedures described here still have significant room for improvement. The most significant remaining systematic errors are associated with the spacecraft orbital velocity.B J.T. Hoeksema

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Imaging Spectroscopy of a White-Light Solar Flare

Cited by 38 publications

References 30 publications

Measurements and Modeling of Total Solar Irradiance in X-Class Solar Flares

Measurements and Modeling of Total Solar Irradiance in X-Class Solar Flares

Bright 30 THz impulsive solar bursts

Observables Processing for the Helioseismic and Magnetic Imager Instrument on the Solar Dynamics Observatory

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