The efficiency of electron acceleration during the impulsive phase of a solar flare

Solar flares are known to be prolific electron accelerators, yet identifying the mechanism(s) for such efficient electron acceleration in solar flare (and similar astrophysical settings) presents a major challenge. This is due in part to a lack of observational constraints related to conditions in the primary acceleration region itself. Accelerated electrons with energies above $\sim$20~keV are revealed by hard X-ray (HXR) bremsstrahlung emission, while accelerated electrons with even higher energies manifest themselves through radio gyrosynchrotron emission. Here we show, for a well-observed flare on 2017~September~10, that a combination of \emph{RHESSI} hard X-ray and and SDO/AIA EUV observations provides a robust estimate of the fraction of the ambient electron population that is accelerated at a given time, with an upper limit of $\sim 10^{-2}$ on the number density of nonthermal ($\ge 20$~keV) electrons, expressed as a fraction of the number density of ambient protons in the same volume. This upper limit is about two orders of magnitude lower than previously inferred from microwave observations of the same event. Our results strongly indicate that the fraction of accelerated electrons in the coronal region at any given time is relatively small, but also that the overall duration of the HXR emission requires a steady resupply of electrons to the acceleration site. Simultaneous measurements of the instantaneous accelerated electron number density and the associated specific electron acceleration rate provide key constraints for a quantitative study of the mechanisms leading to electron acceleration in magnetic reconnection events.Comment: 5 figures, 10 page

Rehabilitation of patients with arthrosis and hip joint injuries

The authors studied remote results in 236 (83,7 %) of 282 patients who had hip replacement. 195 (82,6 %) patients had good results, 38 (16,2 %) - satisfactory, 2 (0,84 %) - unsatisfactory (due to the development of suppurative complications). Lethal outcome was registered in 1 (0,8 %) case (myocardial infarction). 16 patients had bilateral hip replacement. Authors divided rehabilitation measures into local (aimed to the restoration of limb's functions) and general and also by the periods. Precise compliance with standards at the endoprosthesis replacement with further optimal selection of specific physical factors and exercise therapy allow to recover patient to active and qualitative life

Spatiotemporal energy partitioning in a nonthermally dominated two-loop solar flare

Solar flares show remarkable variety in the energy partitioning between thermal and nonthermal components. Those with a prominent nonthermal component but only a modest thermal one are particularly well suited for study of the direct effect of the nonthermal electrons on plasma heating. Here, we analyze such a well-observed, impulsive single-spike nonthermal event, a solar flare SOL2013-11-05T035054, where the plasma heating can be entirely attributed to the energy losses of these impulsively accelerated electrons. Evolution of the energy budget of thermal and nonthermal components during the flare is analyzed using X-ray, microwave, and EUV observations and three-dimensional modeling. The results suggest that (i) the flare geometry is consistent with a two-loop morphology and the magnetic energy is likely released due to interaction between these two loops; (ii) the released magnetic energy is converted to the nonthermal energy of accelerated electrons only, which is subsequently converted to the thermal energy of the plasma; (iii) the energy is partitioned in these two flaring loops in comparable amounts; (iv) one of these flaring loops remained relatively tenuous but rather hot, while the other remained relatively cool but denser than the first. Therefore, this solar flare demonstrates an extreme efficiency of conversion of the free magnetic energy to the nonthermal energy of particle acceleration and the flow of energy into two loops from the nonthermal component to the thermal one with negligible direct heating

DYNAMICS OF BIOCHEMICAL INDICES OF BLOOD SERUM IN RABBITS UNDER THE INFLUENCE OF PHOTOTHERAPY AFTER LOCAL SKIN THERMAL BURN

The article presents data on the dynamics of some biochemical indices in blood serum of rabbits (total protein, alanine aminotransferase, ureal, creatinine, total cholesterol, glucose) during phototherapy of local skin thermal injury using "Bioprone", "Rikta", "Azor", OKN-11M, BOP-4 devices in 5-15 days after wounding. Obtained data testifies to the development of the response of an organism in the form of metabolic processes aimed at the maintenance of constant internal environment but expressed less that at vast burns. Course of phototherapy quite effectively but without distinct differentiation by the method of therapy has positive effect on the normalization of biochemical indices of blood serum

Comparative morphological evaluation of the effectiveness of some practices of light therapy in wound healing (experimental testing)

The article provides information on the efficiency of thermal injury healing in animals (rabbits) under light therapy with «Bioptron», «Ricta», «Azor», 0KN-11M, BOP-4. An analysis has been done of the results of the morphological and planimetric research within 5-15 days after wounding. The factual data received have led to the conclusion that it is advisable to combine different physiotherapeutic practices in wound treatment. Synchronization of processes of an epitelization and maturing of granulyatsionny fabric allowed to recommend for appointment different lengths of waves of optical range in a certain sequence, beginning from ultra-violet beams of short, average range, then laser radiation of an infrared, red range, and also their combination, then to continue influence by the polarized light through standard periods (courses)

Cold Solar Flares I. Microwave Domain

We identify a set of ~100 "cold" solar flares and perform a statistical analysis of them in the microwave range. Cold flares are characterized by a weak thermal response relative to nonthermal emission. This work is a follow up of a previous statistical study of cold flares, which focused on hard X-ray emission to quantify the flare nonthermal component. Here we focus on the microwave emission. The thermal response is represented by the soft X-ray emission measured by the GOES X-ray sensors. We obtain spectral parameters of the flare gyrosynchrotron emission and investigate patterns of the temporal evolution. The main results of the previous statistical study are confirmed: as compared to a "mean" flare, the cold flares have shorter durations, higher spectral peak frequencies, and harder spectral indices above the spectral peak. Nonetheless, there are some cold flares with moderate and low peak frequencies. In a majority of cold flares, we find evidence suggesting the presence of the Razin effect in the microwave spectra, indicative of rather dense flaring loops. We discuss the results in the context of electron acceleration efficiency

Millimeter and X-Ray Emission from the 5 July 2012 Solar Flare

The 5 July 2012 solar flare SOL2012-07-05T11:44 (11:39 – 11:49 UT) with an increasing millimeter spectrum between 93 and 140 GHz is considered. We use space and ground-based observations in X-ray, extreme ultraviolet, microwave, and millimeter wave ranges obtained with the Reuven Ramaty High-Energy Solar Spectroscopic Imager, Solar Dynamics Observatory (SDO), Geostationary Operational Environmental Satellite, Radio Solar Telescope Network, and Bauman Moscow State Technical University millimeter radio telescope RT-7.5. The main parameters of thermal and accelerated electrons were determined through X-ray spectral fitting assuming the homogeneous thermal source and thick-target model. From the data of the Atmospheric Imaging Assembly/SDO and differential-emission-measure calculations it is shown that the thermal coronal plasma gives a negligible contribution to the millimeter flare emission. Model calculations suggest that the observed increase of millimeter spectral flux with frequency is determined by gyrosynchrotron emission of high-energy (≳300 ≳300  keV) electrons in the chromosphere. The consequences of the results are discussed in the light of the flare-energy-release mechanisms.</p

On the origin of 140 GHz emission from the 4 July 2012 solar flare

The sub-THz event observed on the 4 July 2012 with the Bauman Moscow State Technical University Radio Telescope RT-7.5 at 93 and 140~GHz as well as Kislovodsk and Mets\"ahovi radio telescopes, Radio Solar Telescope Network (RSTN), GOES, RHESSI, and SDO orbital stations is analyzed. The spectral flux between 93 and 140 GHz has been observed increasing with frequency. On the basis of the SDO/AIA data the differential emission measure has been calculated. It is shown that the thermal coronal plasma with the temperature above 0.5~MK cannot be responsible for the observed sub-THz flare emission. The non-thermal gyrosynchrotron mechanism can be responsible for the microwave emission near $10$~GHz but the observed millimeter spectral characteristics are likely to be produced by the thermal bremsstrahlung emission from plasma with a temperature of about 0.1~MK.Comment: 18 pages, 6 figure