Validation of computed extreme ultraviolet emission spectra during solar flares

Nishimoto, Shohei; Watanabe, Kyoko; Kawai, Toshiki; Imada, Shinsuke; Kawate, Tomoko

doi:10.1186/s40623-021-01402-7

Cited by 11 publications

(10 citation statements)

References 43 publications

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“…To verify the proposed model, the calculation results, and observed EUV spectra were compared in a statistical manner. The proposed model succeeded in reproducing the EUV flare time-integrated irradiance of the EUV lines, and the correlation coefficient between the proposed model and observations was higher than 0.8 for most of the EUV flare line rise time (Nishimoto et al 2021).…”

Section: X-rays and Extreme Ultraviolet Emissionsmentioning

confidence: 85%

PSTEP: project for solar–terrestrial environment prediction

Kusano¹,

Ichimoto²,

Ishii³

et al. 2021

Earth Planets Space

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Although solar activity may significantly impact the global environment and socioeconomic systems, the mechanisms for solar eruptions and the subsequent processes have not yet been fully understood. Thus, modern society supported by advanced information systems is at risk from severe space weather disturbances. Project for solar–terrestrial environment prediction (PSTEP) was launched to improve this situation through synergy between basic science research and operational forecast. The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. By this project, we sought to answer the fundamental questions concerning the solar–terrestrial environment and aimed to build a next-generation space weather forecast system to prepare for severe space weather disasters. The PSTEP consists of four research groups and proposal-based research units. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

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Section: X-rays and Extreme Ultraviolet Emissionsmentioning

confidence: 85%

PSTEP: project for solar–terrestrial environment prediction

Kusano¹,

Ichimoto²,

Ishii³

et al. 2021

Earth Planets Space

Self Cite

View full text Add to dashboard Cite

show abstract

“…Due to the similar energy ranges of the SXR (0.2-12 keV) and EUV (10-124 eV) regimes, it is expected that the presence of one response implies the other, as they both stem from ablated plasma (see Section 1). However, coupling their time evolution too tightly is known to cause low accuracy in solar modeling (Nishimoto et al 2021), as the EUV emission peaks after the SXR. Some solar EUV flares also have a late phase which is not easily estimated by X-ray comparisons, where a second peak is observed hours after the primary event (Woods et al 2011;Chen et al 2020).…”

Section: Discussionmentioning

confidence: 99%

A 7 Day Multiwavelength Flare Campaign on AU Mic. I. High-time-resolution Light Curves and the Thermal Empirical Neupert Effect

Tristan

Notsu

Kowalski

et al. 2023

ApJ

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We present light curves and flares from a 7 day, multiwavelength observational campaign of AU Mic, a young and active dM1e star with exoplanets and a debris disk. We report on 73 unique flares between the X-ray to optical data. We use high-time-resolution near-UV (NUV) photometry and soft X-ray (SXR) data from the X-ray Multi-Mirror Mission to study the empirical Neupert effect, which correlates the gradual and impulsive phase flaring emissions. We find that 65% (30 of 46) flares do not follow the Neupert effect, which is 3 times more excursions than seen in solar flares, and propose a four-part Neupert effect classification (Neupert, quasi-Neupert, non-Neupert types I and II) to explain the multiwavelength responses. While the SXR emission generally lags behind the NUV as expected from the chromospheric evaporation flare models, the Neupert effect is more prevalent in larger, more impulsive flares. Preliminary flaring rate analysis with X-ray and U-band data suggests that previously estimated energy ratios hold for a collection of flares observed over the same time period, but not necessarily for an individual, multiwavelength flare. These results imply that one model cannot explain all stellar flares and care should be taken when extrapolating between wavelength regimes. Future work will expand wavelength coverage using radio data to constrain the nonthermal empirical and theoretical Neupert effects to better refine models and bridge the gap between stellar and solar flare physics.

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“…5. Diffraction filters provide up to seven orders of magnitude attenuation (Schmidtke, 1968(Schmidtke, , 1970Schmidtke et al, 1974;Nishimoto et al, 2021).…”

Section: Instrument Calibration In Spacementioning

confidence: 99%

Proposal of an instrument design to observe annual changes in Spectral Outgoing Radiation

Schmidtke

Brunner

Jacobi

2023

Preprint

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Abstract. From the wide range of possibilities, we propose an instrument capable of measuring annual changes in global Spectral Outgoing Radiation (SORa) from the entire Earth's surface between 200 nm and 1100 nm with a stability of 0.1 Wm-2 over a period of one solar cycle or beyond. Photomultiplier tubes (PMTs) as detectors provide data with a cadence of one second and high dynamic range. Based on Total Solar Radiation TSI(t) data with a stability of 0.01 Wm-2 per year, Spectral Solar Irradiance SSI(t) can be derived and normalized to ΣSSI(t)=TSI(t) for using the Sun as a referenced radiation source supported by solar modeling. Calibrated by SSI(t), a set of 12 spectrometers with 60 PMTs in total and 16 photometers simultaneously detect SOR(t). This database can also be provided to calibrate other space instruments to allow improved comparison of results. In previous missions in space, it has already been shown that the spectrometer design can detect both solar and terrestrial radiation with high dynamic range. The established measurement technique compensates for degradation through repeated calibration. The instrument also enables the determination of the global green Earth coverage and its annual changes by measuring chlorophyll absorption from 350 nm to 490 nm and 620 nm to 690 nm and green backscatter from 500 nm to 600 nm. Mapping the Earth will also make it possible to track annual local changes in green coverage and to assess the impact of different climate policies and climate engineering actions. Another aspect is the derivation of a correction parameter for the Earth Energy Imbalance derived from changes in green areas. Data evaluation can also include determining further parameters such as the Normalized Difference Vegetation Index, the Enhanced Vegetation Index, and the Global Leaf Area Index.

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Validation of computed extreme ultraviolet emission spectra during solar flares

Cited by 11 publications

References 43 publications

PSTEP: project for solar–terrestrial environment prediction

PSTEP: project for solar–terrestrial environment prediction

A 7 Day Multiwavelength Flare Campaign on AU Mic. I. High-time-resolution Light Curves and the Thermal Empirical Neupert Effect

Proposal of an instrument design to observe annual changes in Spectral Outgoing Radiation

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