Stationary and impulsive injection of electron beams in converging magnetic field

In this work we study time-dependent precipitation of an electron beam injected into a flaring atmosphere with a converging magnetic field by considering collisional and Ohmic losses with anisotropic scattering and pitch angle diffusion. Two injection regimes are investigated: short impulse and stationary injection. The effects of converging magnetic fields with different spatial profiles are compared and the energy deposition produced by the precipitating electrons at different depths and regimes is calculated. The time dependent Fokker-Planck equation for electron distribution in depth, energy and pitch angle was solved numerically by using the summary approximation method. It was found that steady state injection is established for beam electrons at 0.07-0.2 seconds after the injection onset depending on the initial beam parameters. Energy deposition by a stationary beam is strongly dependent on a self-induced electric field but less on a magnetic field convergence. Energy depositions by short electron impulses are found to be insensitive to the self-induced electric field but are strongly affected by a magnetic convergence. Short beam impulses are shown to produce sharp asymmetric hard X-ray bursts within a millisecond timescale often observed in solar flares.Comment: 14 pages, 15 figures, Astronomy and Astrophysics (accepted

Particle acceleration in a reconnecting current sheet: PIC simulation

The acceleration of protons and electrons in a reconnecting current sheet (RCS) is simulated with a particle-in-cell (PIC) 2D3V code for the proton-to-electron mass ratio of 100. The electro-magnetic configuration forming the RCS incorporates all three components of the magnetic field (including the guiding field) and a drifted electric field. PIC simulations reveal that there is a polarisation electric field that appears during acceleration owing to a separation of electrons from protons towards the midplane of the RCS. If the plasma density is low, the polarisation field is weak and the particle trajectories in the PIC simulations are similar to those in the test particle (TP) approach. For the higher plasma density the polarisation field is stronger and it affects the trajectories of protons by increasing their orbits during acceleration. This field also leads to a less asymmetrical abundances of ejected protons towards the midplane in comparison with the TP approach. For a given magnetic topology electrons in PIC simulations are ejected to the same semispace as protons, contrary to the TP results. This happens because the polarisation field extends far beyond the thickness of a current sheet. This field decelerates the electrons, which are initially ejected into the semispace opposite to the protons, returns them back to the RCS, and, eventually, leads to the electron ejection into the same semispace as protons. Energy distribution of the ejected electrons is rather wide and single-peak, contrary to the two-peak narrow-energy distribution obtained in the TP approach. In the case of a strong guiding field, the mean energy of the ejected electrons is found to be smaller than it is predicted analytically and by the TP simulations.Comment: 12 pages, 11 figures, J. Plasma Physics (accepted

Synthesis of stable sols based on titanium dioxide, silicon and metal ion for use in photocatalysis

The paper presents the study of physicochemical processes occurring during the preparation of film-forming solutions, as well as the effect of the component composition on the stability of film-forming solutions over time. Compositions of stable film-forming solutions of TBT, TBT-TEOS, TBT-TEOS-AgNO3 suitable for the formation of thin-film coatings have been developed, and the time periods of stability of rheological properties have been determined. It was found that the addition of tetrabutoxytitanium after the establishment of chemical equilibrium in the solution increases the stability of the film-forming solutions. Optimization of the method of solutions preparation for obtaining films with reproducible physicochemical properties has been carried out

Формирование урожая лекарственных культур (Tanacetum vulgare L., Echinacea purpurea L.) под влиянием эссенциальных микроэлементов

Relevance. A wide range of pharmacological effects of tansy and Echinacea purpurea determine the continuing interest in the study of these cultures. Medicinal crops contain not only a large number of biologically active substances, but also trace elements necessary for normal growth and development. Agronomic bio-enrichment of medicinal raw materials allows you to increase productivity, manage product quality in the direction of enhancing the pharmacological action. Thus, the aim of the work was to study the effect of various doses of zinc acetate on the productivity of two medicinal crops of tansy and Echinacea purpurea.Material and methods. Studies were conducted from 2012 to 2018 on meadow-chernozem soil of the southern forest-steppe of Western Siberia. As objects of research, perennial medicinal crops were chosen – Tanacetum vulgare L. and Echinacea purpurea L. Zinc fertilizers were applied in the background (N125, N135P45K45) used in acetate form.Results. The introduction of zinc fertilizers into the soil contributed to an increase in the yield of medicinal crops in the conditions of the south of Western Siberia. It was revealed that the maximum yield was observed on the variants of 0.75 MAC Zn (Tanacetum vulgare L.) and 0.5 MAC Zn (Echinacea purpurea). Thus, tansy was more responsive to the use of micronutrient fertilizers. The studies established a high correlation relationship (r = 0.88–0.99) between yield indicators and doses of zinc added. The obtained optimal doses of zinc fertilizers (60 and 21.4 kg / ha) can be recommended for growing these crops in order to increase their productivity.Актуальность. Широкий спектр фармакологического действия пижмы обыкновенной и эхинацеи пурпурной определяют постоянный интерес к изучению этих культур. Лекарственные культуры содержат не только большое количество биологически активных веществ, но и микроэлементов, необходимых для нормального роста и развития. Агрономическое биообогащение лекарственного сырья позволяет повысить урожайность, управлять качеством продукции в сторону усиления фармакологического действия. Таким образом, целью работы было изучить влияние различных доз ацетата цинка на продуктивность двух лекарственных культур пижмы обыкновенной и эхинацеи пурпурной.Материалы и методы. Исследования проводили в период с 2012 по 2018 годы на луговочернозёмной почве южной лесостепи Западной Сибири. В качестве объектов исследований были выбраны многолетние лекарственные культуры – пижма обыкновенная и эхинацея пурпурная. Цинковые удобрения использовали в ацетатной форме и вносили по фону (N125, N135P45K45).Результаты. Внесение цинковых удобрений в почву способствовало повышению урожайности лекарственных культур в условиях юга Западной Сибири. Выявлено, что максимальная урожайность отмечалась на вариантах 0,75 ПДК Zn (пижма обыкновенная) и 0,5 ПДК Zn (эхинацея пурпурная). Таким образом, пижма обыкновенная оказалась более отзывчивой на применение микроудобрений. В исследованиях установлена высокая корреляционная взаимосвязь (r=0,88–0,99) между показателями урожайности и дозами вносимого цинка. Полученные оптимальные дозы цинковых удобрений (60 и 21,4 кг д.в./га), могут быть рекомендованы для выращивания данных культур с целью повышения их продуктивности

Prediction of Solar Activity from Solar Background Magnetic Field Variations in Cycles 21-23

yesA comprehensive spectral analysis of both the solar background magnetic field (SBMF) in cycles 21-23 and the sunspot magnetic field in cycle 23 reported in our recent paper showed the presence of two principal components (PCs) of SBMF having opposite polarity, e. g., originating in the northern and southern hemispheres, respectively. Over a duration of one solar cycle, both waves are found to travel with an increasing phase shift toward the northern hemisphere in odd cycles 21 and 23 and to the southern hemisphere in even cycle 22. These waves were linked to solar dynamo waves assumed to form in different layers of the solar interior. In this paper, for the first time, the PCs of SBMF in cycles 21-23 are analyzed with the symbolic regression technique using Hamiltonian principles, allowing us to uncover the underlying mathematical laws governing these complex waves in the SBMF presented by PCs and to extrapolate these PCs to cycles 24-26. The PCs predicted for cycle 24 very closely fit (with an accuracy better than 98%) the PCs derived from the SBMF observations in this cycle. This approach also predicts a strong reduction of the SBMF in cycles 25 and 26 and, thus, a reduction of the resulting solar activity. This decrease is accompanied by an increasing phase shift between the two predicted PCs (magnetic waves) in cycle 25 leading to their full separation into the opposite hemispheres in cycle 26. The variations of the modulus summary of the two PCs in SBMF reveals a remarkable resemblance to the average number of sunspots in cycles 21-24 and to predictions of reduced sunspot numbers compared to cycle 24: 80% in cycle 25 and 40% in cycle 26

The Effects of Return Current on Hard X-Ray Photon and Electron Spectra in Solar Flares

NoThe effect of a self-induced electric field is investigated analytically and numerically on differential and mean electron spectra produced by beam electrons during their precipitation into a flaring atmosphere as well as on the emitted hard X-ray (HXR) photon spectra. The induced electric field is found to be a constant in upper atmospheric layers and to fall sharply in the deeper atmosphere from some "turning point" occurring either in the corona (for intense and softer beams) or in the chromosphere (for weaker and harder beams). The stronger and softer the beam, the higher the electric field before the turning point and the steeper its decrease after it. Analytical solutions are presented for the electric fields, which are constant or decreasing with depth, and the characteristic "electric" stopping depths are compared with the "collisional" ones. A constant electric field is found to decelerate precipitating electrons and to significantly reduce their number in the upper atmospheric depth, resulting in their differential spectra flattening at lower energies (<100 keV). While a decreasing electric field slows down the electron deceleration, allowing them to precipitate into deeper atmospheric layers than for a constant electric field, the joint effect of electric and collisional energy losses increases the energy losses by lower energy electrons compared to pure collisions and results in maxima at energies of 40-80 keV in the differential electron spectra. This, in turn, leads to the maxima in the mean source electron spectra and to the "double power law" HXR photon spectra (with flattening at lower energies) similar to those reported from the RHESSI observations. The more intense and soft the beams are, the stronger is the lower energy flattening and the higher is the "break" energy where the flattening occurs

Formation of a crop of medicinal crops (<i>Tanacetum vulgare</i> L., <i>Echinacea purpurea</i> L.) under influence of essential microelements

Relevance. A wide range of pharmacological effects of tansy and Echinacea purpurea determine the continuing interest in the study of these cultures. Medicinal crops contain not only a large number of biologically active substances, but also trace elements necessary for normal growth and development. Agronomic bio-enrichment of medicinal raw materials allows you to increase productivity, manage product quality in the direction of enhancing the pharmacological action. Thus, the aim of the work was to study the effect of various doses of zinc acetate on the productivity of two medicinal crops of tansy and Echinacea purpurea.Material and methods. Studies were conducted from 2012 to 2018 on meadow-chernozem soil of the southern forest-steppe of Western Siberia. As objects of research, perennial medicinal crops were chosen – Tanacetum vulgare L. and Echinacea purpurea L. Zinc fertilizers were applied in the background (N125, N135P45K45) used in acetate form.Results. The introduction of zinc fertilizers into the soil contributed to an increase in the yield of medicinal crops in the conditions of the south of Western Siberia. It was revealed that the maximum yield was observed on the variants of 0.75 MAC Zn (Tanacetum vulgare L.) and 0.5 MAC Zn (Echinacea purpurea). Thus, tansy was more responsive to the use of micronutrient fertilizers. The studies established a high correlation relationship (r = 0.88–0.99) between yield indicators and doses of zinc added. The obtained optimal doses of zinc fertilizers (60 and 21.4 kg / ha) can be recommended for growing these crops in order to increase their productivity