Determination of electron density in plasma by the number of the extreme resolved line

Kurochka, L. N.; Maslennikova, L. B.

doi:10.1007/bf00156548

Cited by 28 publications

(11 citation statements)

References 9 publications

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“…The Inglis-Teller relation (Kurochka & Maslennikova, 1970) relates the last member of the Hydrogen series that is resolved to the electron density that induces the Stark broadening. HP91 used this technique to deduce n e ∼ 3 × 10 13 cm −3 in the Great Flare on AD Leo, whereas Worden et al (1984) According to the formula for linear Stark broadening (Sutton, 1978, see also Johns-Krull et al (1997)), the amount of line broadening (inÅ) is proportional to Donati-Falchi et al (1985).…”

Section: Broadening and Decrement Discussion And Summarymentioning

confidence: 99%

“…Balmer line broadening has been studied extensively in stellar flares (Doyle et al, 1988;Hawley & Pettersen, 1991;Jevremovic et al, 1998;García-Alvarez et al, 2002;Hawley et al, 2003;Paulson et al, 2006;Fuhrmeister et al, 2008Fuhrmeister et al, , 2011. The cause of line broadening remains an open question, as it has been attributed to both Doppler and Stark effects (see discussion in Kurochka & Maslennikova, 1970). The Doppler effect may contribute to broadening through mass motions and thermal velocities in the flare atmosphere (Eason et al, 1992).…”

Section: Line Broadening Backgroundmentioning

confidence: 99%

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TIME-RESOLVED PROPERTIES AND GLOBAL TRENDS IN dMe FLARES FROM SIMULTANEOUS PHOTOMETRY AND SPECTRA

Kowalski

Hawley

Wisniewski

et al. 2013

ApJS

233

399

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We present a homogeneous survey of near-ultraviolet (NUV) /optical line and continuum emission during twenty M dwarf flares with simultaneous, high cadence photometry and spectra. These data were obtained to study the white-light continuum components to the blue and red of the Balmer jump to break the degeneracy with fitting emission mechanisms to broadband colors and to provide constraints for radiative-hydrodynamic flare models that seek to reproduce the white-light flare emission. The main results from the continuum analysis are the following: 1) the detection of Balmer continuum (in emission) that is present during all flares, with a wide range of relative contribution to the continuum flux in the NUV; 2) a blue continuum at the peak of the photometry that is linear with wavelength from λ = 4000 − 4800Å, matched by the spectral shape of hot, blackbody emission with typical temperatures of 10 000 − 12 000 K; 3) a redder continuum apparent at wavelengths longer than Hβ; this continuum becomes relatively more important to the energy budget during the late gradual phase. The hot blackbody component and redder continuum component (which we call "the conundruum") have been detected in previous U BV R colorimetry studies of flares. With spectra, one can compare the properties and detailed timings of all three components. Using time-resolved spectra during the rise phase of three flares, we calculate the speed of an expanding flare region assuming a simple geometry; the speeds are found to be ∼5 -10 km s −1 and 50 -120 km s −1 , which are strikingly consistent with the speeds at

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Section: Broadening and Decrement Discussion And Summarymentioning

confidence: 99%

Section: Line Broadening Backgroundmentioning

confidence: 99%

TIME-RESOLVED PROPERTIES AND GLOBAL TRENDS IN dMe FLARES FROM SIMULTANEOUS PHOTOMETRY AND SPECTRA

Kowalski

Hawley

Wisniewski

et al. 2013

ApJS

233

399

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“…The broadening of the neutral hydrogen lines depends on thermal motions, but also on the Stark effect, and on the collisions with free electrons. It therefore depends, among other things, on , so in principle the broadening can be used to estimate (see, e.g., Kurochka and Maslennikova 1970).…”

Section: Diagnostics Of Electron Densitiesmentioning

confidence: 99%

Solar UV and X-ray spectral diagnostics

Zanna

Mason

2018

Living Rev Sol Phys

222

139

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X-ray and ultraviolet (UV) observations of the outer solar atmosphere have been used for many decades to measure the fundamental parameters of the solar plasma. This review focuses on the optically thin emission from the solar atmosphere, mostly found at UV and X-ray (XUV) wavelengths, and discusses some of the diagnostic methods that have been used to measure electron densities, electron temperatures, differential emission measure (DEM), and relative chemical abundances. We mainly focus on methods and results obtained from high-resolution spectroscopy, rather than broad-band imaging. However, we note that the best results are often obtained by combining imaging and spectroscopic observations. We also mainly focus the review on measurements of electron densities and temperatures obtained from single ion diagnostics, to avoid issues related to the ionisation state of the plasma. We start the review with a short historical introduction on the main XUV high-resolution spectrometers, then review the basics of optically thin emission and the main processes that affect the formation of a spectral line. We mainly discuss plasma in equilibrium, but briefly mention non-equilibrium ionisation and non-thermal electron distributions. We also summarise the status of atomic data, which are an essential part of the diagnostic process. We then review the methods used to measure electron densities, electron temperatures, the DEM, and relative chemical abundances, and the results obtained for the lower solar atmosphere (within a fraction of the solar radii), for coronal holes, the quiet Sun, active regions and flares.

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“…The highest order Balmer lines that are resolved have been used with the Inglis-Teller relation to probe the charge density in flares (Kurochka & Maslennikova 1970;Hawley & Pettersen 1991). To account for self-consistent optical depth, density, and temperature variations over the regions of line formation, we use our modeling method to revisit the broadening predictions from recent RHD flare models of dMe flares that produce large values of the electron density (n 10 e 15  cm −3 ).…”

Section: Balmer Line Broadening In Stellar Flaresmentioning

confidence: 99%

Hydrogen Balmer Line Broadening in Solar and Stellar Flares

Kowalski

Allred

Uitenbroek

et al. 2017

ApJ

108

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The broadening of the hydrogen lines during flares is thought to result from increased charge (electron, proton) density in the flare chromosphere. However, disagreements between theory and modeling prescriptions have precluded an accurate diagnostic of the degree of ionization and compression resulting from flare heating in the chromosphere. To resolve this issue, we have incorporated the unified theory of electric pressure broadening of the hydrogen lines into the non-LTEradiative-transfer code RH. This broadening prescription produces a much more realistic spectrum of the quiescent, A0 star Vega compared to the analytic approximations used as a damping parameter in the Voigt profiles. We test recent radiative-hydrodynamic (RHD) simulations of the atmospheric response to high nonthermal electron beam fluxes with the new broadening prescription and find that the Balmer lines are overbroadened at the densest times in the simulations. Adding many simultaneously heated and cooling model loops as a "multithread" model improves the agreement with the observations. We revisit the threecomponent phenomenological flare model of the YZ CMi Megaflare using recent and new RHD models. The evolution of the broadening, line flux ratios, and continuum flux ratios are well-reproduced by a multithread model with high-flux nonthermal electron beam heating, an extended decay phase model, and a "hot spot" atmosphere heated by an ultrarelativistic electron beam with reasonable filling factors: ∼0.1%, 1%, and 0.1% of the visible stellar hemisphere, respectively. The new modeling motivates future work to understand the origin of the extended gradual phase emission.

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Determination of electron density in plasma by the number of the extreme resolved line

Cited by 28 publications

References 9 publications

TIME-RESOLVED PROPERTIES AND GLOBAL TRENDS IN dMe FLARES FROM SIMULTANEOUS PHOTOMETRY AND SPECTRA

TIME-RESOLVED PROPERTIES AND GLOBAL TRENDS IN dMe FLARES FROM SIMULTANEOUS PHOTOMETRY AND SPECTRA

Solar UV and X-ray spectral diagnostics

Hydrogen Balmer Line Broadening in Solar and Stellar Flares

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