2D and 3D simulations of the penetration of neutral particles into the plasma with parameters corresponding to the ohmic heating regime in the L-2M stellarator were performed, and the simulation ...results were compared. Radial distributions of neutrals density in plasma and model energy spectra of fluxes of charge-exchange atoms escaping from the plasma were obtained. For the conditions of the ohmic heating regime in the L-2M stellarator, the limiting plasma densities were determined, above which it is necessary to take into account the recombination processes when performing simulations. Comparison of the model energy spectra of fluxes of charge-exchange atoms escaping from the plasma with experimental data made it possible to construct the radial distributions of the neutrals density in absolute units. In this case, the calculated density of neutrals at the plasma axis turned out to be ~10
15
m
–3
, which is four orders of magnitude less than the density of charged particles 10
19
m
–3
.
Plasma was heated at the second harmonic of electron cyclotron resonance (ECR) in the L-2M stellarator and the T-10 tokamak. The concept of equivalent tokamak and stellarator discharges was extended ...to the case of both full and partial absorption of EC power. Comparison of experimental electron temperature profiles with profiles calculated using the canonical profiles transport model allows us to estimate the efficiency of ECR heating in the L-2M discharges without suprathermal electrons, which distort the distribution function, preventing reliable measurements of temperature. The dependence of the ECR heating efficiency on the plasma density was obtained, describing experiments on the L-2M and TJ-II stellarators, and on the T-10 tokamak. The energy characteristics (the stored energy and the confinement time) for L-2M discharges were calculated. Predictions for ECR heating in the T-15MD tokamak are considered. The features of solving the ill-posed transport problem for the L-2M are discussed.
The results are presented from measurements of the power absorbed in plasma of the L-2M stellarator in experiments on the electron cyclotron resonance (ECR) plasma heating at the second harmonic of ...the gyrofrequency. Hydrogen plasma was created and heated in the stellarator vacuum chamber as a result of the resonance absorption of microwave power supplied by the gyrotrons in the pulse-periodic operation regime. The total energy of the toroidal plasma column and the absorbed power were measured using the diamagnetic diagnostics. The shielding effect of the metal vacuum chamber on the diamagnetic signal measurements was taken into account. It was ascertained that, during the axial ECR heating, up to 90% of the inputted gyrotron power is absorbed in the plasma that is consistent with the theoretical estimates.
Results of measuring longitudinal electric current excited in the toroidal plasma of the L-2M stellarator as a result of high-power pulsed microwave heating (power of up to 600 kW, pulse duration of ...up to 20 ms) are presented. Microwave radiation generated by gyrotrons and at frequency of 75 GHz, the second harmonic of the electron cyclotron resonance for magnetic field with induction
B
= 1.34 T in the plasma-column center, was used in the experiments for creation and heating of plasma in the stellarator. Diagnostic systems of the stellarator designed for detection of changes in transverse and poloidal magnetic fields with time were used for measuring currents in plasma. It is demonstrated that the presence of ohmic-heating iron transformer in stellarator construction substantially affects the temporal dynamics of equilibrium currents due to considerable inductance of the toroidal plasma column. The magnitude of the current excited in plasma can be as high as 7 kA upon compensation of inductance of these devices.
Physiological and biochemical parameters of blood plasma of laboratory animals were evaluated when using, in addition to the main diet, a food substance with known biocorrecting properties - a ...probiotic emulsion administered orally, based on wheat germ oil and biomass of a consortium of lacto and bifidobacteria, including Str. thermophiles, B. bifidum, B. longum, B. adolescentis, L. acidophilus, L. plantarum, L. fermentum. The object of experimental studies was male and female growing white rats of the Wistar line in the amount of 60 individuals, comprising 2 experimental and 2 control groups of 15 individuals each. Evaluation of the average values of physiological indicators showed an increase in the horizontal and vertical motor activity of the white rats of the experimental group by an average of 16-18 % and 60-70%, an increase in the number of examined minks by 10-12 %, a significant decrease in the level of grooming and defecation. It was established that the clinical and biochemical parameters of the blood plasma of white rats were within the physiological limits. The concentrations of total protein, glucose, high and low density lipoproteins, alanine aminotransferase, aspartate aminotransferase by group differed slightly. It was found that the concentration of total cholesterol and LDL in the test groups of females and males at the end of the experimental studies decreased by 2.1-2.2 % and 4.1-5.8 %. The bilirubinaikreatinin concentration was slightly reduced in the experimental group of females and males by 1.1-1.3 % and 2.1-4.2 %, respectively. A significant increase in hemoglobin and red blood cells by 2.6-7.1 % and 4.8-5.1 % was recorded.
In experiments on multipulse on-axis electron cyclotron resonance heating (ECRH) of plasma by a series of microwave pulses at the L-2M stellarator, several phases of plasma energy loss were observed: ...the short stage of low-energy loss, the stage of rapid increase in energy loss, the quasi-steady stage, and the relaxation stage between the heating pulses. In the stage of rapid increase in energy loss, the energy loss power is two or more times higher than that in the relaxation stage at the same energy of the plasma column. Short-wavelength plasma density fluctuations were measured using both the ordinary and extraordinary microwave collective scattering technique. It is found that, in the quasi-steady stage, the amplitude of density fluctuations is much lower than that in the preceding heating stages. The fluctuation amplitude lowers just after the restructuring of the density profile and establishment of a steady-state hollow density profile due to the density pump-out effect. The amplitude of large-scale density fluctuations at the plasma periphery recorded by a Doppler reflectometer remains unchanged during the ECRH pulses and in the time intervals between them. However, when the stage of rapid increase in energy loss begins, the shape of the density fluctuation spectrum changes significantly. The initially narrow spectrum with one peak near the zero frequency broadens, the amplitude of the central peak decreases, and two additional peaks at frequencies of 0.7 and −0.7 MHz appear.
Impurity injection into plasma caused by the sputtering of the wall coating in the L-2M stellarator during auxiliary electron cyclotron resonance heating leads to a change in the level of plasma ...density fluctuations with frequencies above 0.25 MHz: suppression of long-wavelength (
k
⊥
= 2 cm
–1
) density fluctuations in the edge plasma, intensification of short-wavelength (
k
⊥
= 30 cm
–1
) and long-wavelength (
k
⊥
= 1 cm
–1
) fluctuations at the midradius of the plasma column, and intensification of short-wavelength fluctuations (
k
⊥
= 20 cm
–1
) in the plasma center (including the gyroresonance region). At the same time, the level of fluctuations with frequencies below 0.25 MHz remains unchanged. In the edge plasma, a decrease in the plasma potential and suppression of its fluctuations is observed during impurity injection, which also causes an increase in MHD activity.
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