EUV SpectroPhotometer (ESP) in Extreme Ultraviolet Variability Experiment (EVE): Algorithms and Calibrations

Didkovsky, L. V.; Judge, D. L.; Wieman, Seth; Woods, T. N.; Jones, A. R.

doi:10.1007/s11207-009-9485-8

Cited by 61 publications

(66 citation statements)

References 17 publications

(6 reference statements)

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“…The wavelength coverage of all instruments is shown in Figure 3, along with the solar-cycle minimum spectrum obtained with the prototype EVE onboard a sounding rocket flight on 14 April 2008 (Chamberlin et al, 2009). Eparvier et al (2004), Crotser et al (2004Crotser et al ( , 2007, , Didkovsky et al (2007Didkovsky et al ( , 2010, and Hock et al (2010) provide details of the optical designs for the EVE instruments, but a brief overview of the instruments is included here.…”

Section: Eve Instrumentationmentioning

confidence: 99%

“…The ESP measurements are made at a high time cadence (0.25 seconds) and so are useful as quick indicators of space-weather events such as flares. Didkovsky et al (2007Didkovsky et al ( , 2010 provide more details about USC's ESP and its calibration results.…”

Section: Eve Instrumentationmentioning

confidence: 99%

“…The sum of the quadrants gives the solar irradiance in this bandpass. Differencing the quadrants allows for determination of the pointing of the ESP and can also provide the location of flares on the solar disk (Didkovsky et al, 2010). The ESP has a filter-wheel mechanism with Al foil filters for solar measurements, a blank position for dark measurements, and a fused-silica window to check for visible stray light.…”

Section: Esp Instrumentmentioning

confidence: 99%

“…The grazing-incidence spectrograph in EVE implements a new, innovative grating design whereby the CCD is near normal incidence, instead of the traditional grazing incidence, so that this spectrograph achieves much higher sensitivity . The EUV Spectrophotometer (ESP) instrument in EVE is an expanded version of the SOHO Solar EUV Monitor (SEM) with multiple channels and with a quadrant photodiode that can provide in realtime the location of flares on the solar disk (Didkovsky et al, 2010). As a final technology example, the EVE Solar Aspect Monitor (SAM) channel is a pinhole camera to provide not only alignment information for EVE in visible light but also solar X-ray spectra and images through detecting individual X-ray photon events (Hock et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Hock et al (2010) and Didkovsky et al (2010) provide more complete instrument description and details of pre-flight calibration results.…”

Section: Introductionmentioning

confidence: 99%

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Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Overview of Science Objectives, Instrument Design, Data Products, and Model Developments

Woods

Eparvier

Hock

et al. 2010

The Solar Dynamics Observatory

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The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth's upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105 nm with unprecedented spectral resolution (0.1 nm), temporal cadence (ten seconds), and accuracy (20%). EVE includes several irradiance instruments: The Multiple EUV Grating Spectrographs (MEGS)-A is a grazingincidence spectrograph that measures the solar EUV irradiance in the 5 to 37 nm range with 0.1-nm resolution, and the MEGS-B is a normal-incidence, dual-pass spectrograph that measures the solar EUV irradiance in the 35 to 105 nm range with 0.1-nm resolution. To provide MEGS in-flight calibration, the EUV SpectroPhotometer (ESP) measures the solar EUV irradiance in broadbands between 0.1 and 39 nm, and a MEGS-Photometer measures the Sun's bright hydrogen emission at 121.6 nm. The EVE data products include a near real-time space-weather product (Level 0C), which provides the solar EUV irradiance in specific bands and also spectra in 0.1-nm intervals with a cadence of one minute and with a time delay of less than 15 minutes. The EVE higher-level products are Level 2 with the solar EUV irradiance at higher time cadence (0.25 seconds for photometers and ten seconds for spectrographs) and Level 3 with averages of the solar irradiance over a day and over each one-hour period. The EVE team also plans to advance existing models of solar EUV irradiance and to operationally use the EVE measurements in models of Earth's ionosphere and thermosphere. Improved understanding of the evolution of solar flares and extending the various models to incorporate solar flare events are high priorities for the EVE team.

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Section: Eve Instrumentationmentioning

confidence: 99%

Section: Eve Instrumentationmentioning

confidence: 99%

Section: Esp Instrumentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Hock et al (2010) and Didkovsky et al (2010) provide more complete instrument description and details of pre-flight calibration results.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Overview of Science Objectives, Instrument Design, Data Products, and Model Developments

Woods

Eparvier

Hock

et al. 2010

The Solar Dynamics Observatory

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Ionospheric total electron contents (TECs) as indicators of solar EUV changes during the last two solar minima

Didkovsky

Wieman

2014

JGR Space Physics

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During the extended solar minimum from 2007 to 2009 anomalously low densities were observed in the Earth's thermosphere. Solar activity for the minimum of Solar Cycles 23 and 24 was lower than for Solar Cycles 22 and 23. However, a comparison of global daily averaged Total Electron Content (TEC) for these two solar minima does not show any significant difference. Why these significant changes between the 2008 and 1996 minima were observed in the He II EUV absolute irradiance and not in the global TEC for which EUV irradiance is one of the primary drivers is not well understood and may be interpreted as an effect of EUV instrument degradation. In this study, we analyze TEC data from 1995 to 2013 from the Center for Orbit Determination in Europe (CODE) database and compare global daily averaged TEC signal with TEC sectorial spherical harmonics which reflect a narrower temporal and spatial integration of the TEC in the Earth's ionosphere. Our analyses of both TEC data and errors show significant decreases of sectorial TECs for the 2008 and 2009 minimum compared to the minimum of 1996. We also compare the most recent version of Solar and Heliospheric Observatory/Solar EUV Monitor (SOHO/SEM) He II absolute EUV irradiance with the measurements from the Solar Dynamics Observatory/Extreme Ultraviolet Variability Experiment channels. This comparison shows that the EUV He II irradiance was about 12 ± 4% lower for the minimum of 2008 and 2009 compared to the minimum of 1996 when a low-pass filter with a 365 day window was used.

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Soft X‐ray irradiance measured by the Solar Aspect Monitor on the Solar Dynamic Observatory Extreme ultraviolet Variability Experiment

et al. 2016

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The Solar Aspect Monitor (SAM) is a pinhole camera on the Extreme ultraviolet Variability Experiment (EVE) aboard the Solar Dynamics Observatory. SAM projects the solar disk onto the CCD through a metallic filter designed to allow only solar photons shortward of 7 nm to pass. Contamination from energetic particles and out‐of‐band irradiance is, however, significant in the SAM observations. We present a technique for isolating the 0.01–7 nm integrated irradiance from the SAM signal to produce the first results of broadband irradiance for the time period from May 2010 to May 2014. The results of this analysis agree with a similar data product from EVE's EUV SpectroPhotometer to within 25%. We compare our results with measurements from the Student Nitric Oxide Explorer Solar X‐ray Photometer and the Thermosphere Ionosphere Mesosphere Energetics and Dynamics Solar EUV Experiment at similar levels of solar activity. We show that the full‐disk SAM broadband results compared well to the other measurements of the 0.01–7 nm irradiance. We also explore SAM's capability toward resolving spatial contribution from regions of solar disk in irradiance and demonstrate this feature with a case study of several strong flares that erupted from active regions on 11 March 2011.

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EUV SpectroPhotometer (ESP) in Extreme Ultraviolet Variability Experiment (EVE): Algorithms and Calibrations

Cited by 61 publications

References 17 publications

Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Overview of Science Objectives, Instrument Design, Data Products, and Model Developments

Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Overview of Science Objectives, Instrument Design, Data Products, and Model Developments

Ionospheric total electron contents (TECs) as indicators of solar EUV changes during the last two solar minima

Soft X‐ray irradiance measured by the Solar Aspect Monitor on the Solar Dynamic Observatory Extreme ultraviolet Variability Experiment

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