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Measurements of polarized electron-nucleon scattering can be realized at the TESLA linear collider facility with projected luminosities that are about two orders of magnitude higher than those expected of other experiments at comparable…

We present the angular distribution of electrons knocked out from an atom in a fast charge particle collision at small momentum transfer. It is determined not only by dipole but also by quadrupole transitions, the contribution of which can…

Atomic Physics · Physics 2015-06-03 M. Ya. Amusia , L. V. Chernysheva , E. Z. Liverts

High-energy data of accreting white dwarfs give access to the regime of the primary accretion-induced energy release and the different proposed accretion scenarios. We perform XMM-Newton observations of polars selected due to their ROSAT…

Solar and Stellar Astrophysics · Physics 2014-07-02 I. Traulsen , K. Reinsch , A. D. Schwope

Context: The common flare scenario comprises an acceleration site in the corona and particle transport to the chromosphere. Using satellites available to date it has become possible to distinguish between the two processes of acceleration…

Astrophysics · Physics 2011-02-19 Marina Battaglia , Arnold O. Benz

The polarisation of x-ray photons can be determined by measuring the direction of emission of a K-shell photoelectron. Effective exploitation of this effect below 10 keV would allow development of a highly sensitive x-ray polarimeter…

We present a statistical study of chromospheric evaporation in solar flares using simultaneous observations by the RHESSI X-ray telescope and the IRIS UV spectrograph. The results are compared with radiation hydrodynamic flare models from…

Solar and Stellar Astrophysics · Physics 2019-01-23 Viacheslav M Sadykov , Alexander G Kosovichev , Ivan N Sharykin , Graham S Kerr

We are interested in electrons kinetics in a stellar atmosphere to validate or invalidate the usually accepted hypothesis of thermalisation of electrons. For this purpose, we calculate the velocity distribution function of electrons by…

Astrophysics · Physics 2007-05-23 L. Chevallier

It has been noted for a long time that the spectra of observed continuum emissions in many solar flares are consistent with double power laws with a hardening at energies $\sim > $ 300 keV. It is now largely believed that at least in…

Solar and Stellar Astrophysics · Physics 2015-06-15 Gang. Li , XiangLiang Kong , Gary Zank , Yao Chen

Decades of astrophysical observations have convincingly shown that soft X-ray (SXR; ~0.1--10 keV) emission provides unique diagnostics for the high temperature plasmas observed in solar flares and active regions. SXR observations critical…

Instrumentation and Methods for Astrophysics · Physics 2017-01-04 Amir Caspi , Albert Y. Shih , Harry P. Warren , Marek Stęślicki , Janusz Sylwester

In the magnetar model, the quiescent non-thermal soft X-ray emission from Anomalous X-ray Pulsars and Soft-Gamma Repeaters is thought to arise from resonant comptonization of thermal photons by charges moving in a twisted magnetosphere.…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Rodrigo Fernández , Shane W. Davis

Nonlinear Thomson scattering of an electron motion in a combining field constituted by an elliptically polarized laser and a background magnetic field is investigated. The dependence of the electron trajectories, the fundamental frequency,…

Optics · Physics 2022-06-28 Hong Xiao , Cui-Wen Zhang , Hai-Bo Sang , Bai-Song Xie

A spectrograph is an optical instrument that disperses photons of different energies into distinct directions and space locations, and images photon spectra on a position-sensitive detector. Spectrographs consist of collimating, angular…

Optics · Physics 2015-06-11 Yuri Shvyd'ko

Context: Solar flares release a large fraction of their energy into non-thermal electrons, but it is not clear where and how. Bremsstrahlung X-rays are observed from the corona and chromosphere. Aims: We aim to characterize the acceleration…

Astrophysics · Physics 2009-11-11 Marina Battaglia , Arnold O. Benz

Polarimetric measurements, especially if extended at high energy, are expected to provide important insights into the mechanisms underlying the acceleration of relativistic particles in jets. In a previous work we have shown that the…

High Energy Astrophysical Phenomena · Physics 2020-09-09 F. Tavecchio , M. Landoni , L. Sironi , P. Coppi

A decade of X-ray stellar observations with Chandra and XMM-Newton has led to significant advances in our understanding of the physical processes at work in hot (magnetized) plasmas in stars and their immediate environment, providing new…

Solar and Stellar Astrophysics · Physics 2010-08-26 Paola Testa

We compute rest-frame reflection spectra and the corresponding energy-dependent linear polarization degree and angle for (un)polarized single-temperature blackbody spectra impinging on a partially ionized constant-density optically thick…

High Energy Astrophysical Phenomena · Physics 2026-05-27 J. Podgorný , M. Dovčiak , R. Goosmann , F. Marin , L. Marra , G. Matt , A. Różańska , R. Taverna

The hard X-ray emission in a solar flare is typically characterized by a number of discrete sources, each with its own spectral, temporal, and spatial variability. Establishing the relationship amongst these sources is critical to determine…

Solar and Stellar Astrophysics · Physics 2018-08-08 Federica Sciacchitano , Alberto Sorrentino , A Gordon Emslie , Anna Maria Massone , Michele Piana

The statistical characteristic of stellar flares at optical bands has received an extensive study, but it remains to be studied at soft X-ray bands, in particular for solar-type stars. Here, we present a statistical study of soft X-ray…

Solar and Stellar Astrophysics · Physics 2024-01-19 Zhanhao Zhao , Ziqian Hua , Xin Cheng , Zhiyuan Li , Mingde Ding

We present the science case for a broadband X-ray imager with high-resolution spectroscopy, including simulations of X-ray spectral diagnostics of both active regions and solar flares. This is part of a trilogy of white papers discussing…

EGRET (20 MeV to 30 GeV) on board the Compton GRO has observed high-energy emission from about 40-50 Active Galactic Nuclei. Theoretical models of this emission based on the upscattering of thermal disk photons by cooling, relativistic…

Astrophysics · Physics 2010-12-03 Marco Fatuzzo , Fulvio Melia