Nonclassical Transport and Particle-Field Coupling: from Laboratory Plasmas to the Solar Wind

Understanding transport of thermal and suprathermal particles is a fundamental issue in laboratory, solar-terrestrial, and astrophysical plasmas. For laboratory fusion experiments, confinement of particles and energy is essential for sustaining the plasma long enough to reach burning conditions. For solar wind and magnetospheric plasmas, transport properties determine the spatial and temporal distribution of energetic particles, which can be harmful for spacecraft functioning, as well as the entry of solar wind plasma into the magnetosphere. For astrophysical plasmas, transport properties determine the efficiency of particle acceleration processes and affect observable radiative signatures. In all cases, transport depends on the interaction of thermal and suprathermal particles with the electric and magnetic fluctuations in the plasma. Understanding transport therefore requires us to understand these interactions, which encompass a wide range of scales, from magnetohydrodynamic to kinetic scales, with larger scale structures also having a role. The wealth of transport studies during recent decades has shown the existence of a variety of regimes that differ from the classical quasilinear regime. In this paper we give an overview of nonclassical plasma transport regimes, discussing theoretical approaches to superdiffusive and subdiffusive transport, wave–particle interactions at microscopic kinetic scales, the influence of coherent structures and of avalanching transport, and the results of numerical simulations and experimental data analyses. Applications to laboratory plasmas and space plasmas are discussed.     

Application of the graph-analytical method of tree risk assessment to study survivability of small trust liquid rocket engines

The present paper discusses a need to develop a methodology of predicting the reliability of small thrust liquid rocket engines with a flow section made of composite materials under actual operating conditions for their successful practical use in the propulsion systems.     

Potential Effects of Surface Temperature Variations and Disturbances and Thermal Convection on the Mars InSight HP<Superscript>3</Superscript> Heat-Flow Determination

The HP³ instrument on the InSight lander mission will measure subsurface temperatures and thermal conductivities from which heat flow in the upper few meters of the regolith at the landing site will be calculated. The parameter to be determined is steady-state conductive heat flow, but temperatures may have transient perturbations resulting from surface temperature changes and there could be a component of thermal convection associated with heat transport by vertical flow of atmospheric gases over the depth interval of measurement. The experiment is designed so that it should penetrate to a depth below which surface temperature perturbations are smaller than the required measurement precision by the time the measurements are made. However, if the measurements are delayed after landing, and/or the probe does not penetrate to the desired depth, corrections may be necessary for the transient perturbations. Thermal convection is calculated to be negligible, but these calculations are based on unknown physical properties of the Mars regolith. The effects of thermal convection should be apparent at shallow depths where transient thermal perturbations would be observed to deviate from conductive theory. These calculations were required during proposal review and their probability of predicting a successful measurement a prerequisite for mission approval. However, their uncertainties lies in unmeasured physical parameters of the Mars regolith.     

Operating characteristics of a high radius pre-swirl cooling system

An experimental investigation into pre-swirl effectiveness and receiver hole discharge coefficient characteristics for a high radius injection pre-swirl cooling systems was carried out on a physically representative experimental rig with a 450 mm diameter rotor.The receiver holes and pre-swirl nozzle were located at a radius of 181 mm and 180 mm respectively.The experimental work was mainly conducted at 5 000～12 000 r/min,4 bar absolute pressure and 1.132 kg/s air supply.The maximum air supply temperature was 190 ℃.Pressure and temperature distributions in the pre-swirl system were examined with an emphasis on the velocity effectiveness of the pre-swirl system as a whole and on the discharge coefficients of the rotating 'receiver holes' in the rotor.The results showed that the velocity effectiveness increased with increasing swirl ratio resulting in reduced blade cooling flow temperature.Different seal flow configurations caused very different effectiveness at different speeds,but outflow through the inner and outer seals always gave the highest effectiveness compared other configurations.Increasing the seal flow rate reduced the effectiveness.For the coefficient of discharge,except for the low speed range,it increased with increase in swirl ratio for most speeds.      

Erratum to: Determination of the Probability of Collision of Near-Earth Space Objects Taking into Account Form and Orientation

Cosmic Research - An Erratum to this paper has been published: https://doi.org/10.1134/S0010952521120030     

Longitudinal variation of the equatorial ionosphere: Modeling and experimental results

We describe a new version of the Parameterized Regional Ionospheric Model (PARIM) which has been modified to include the longitudinal dependences. This model has been reconstructed using multidimensional Fourier series. To validate PARIM results, the South America maps of critical frequencies for the E (foE) and F (foF2) regions were compared with the values calculated by Sheffield Plasmasphere-Ionosphere Model (SUPIM) and IRI representations. PARIM presents very good results, the general characteristics of both regions, mainly the presence of the equatorial ionization anomaly, were well reproduced for equinoctial conditions of solar minimum and maximum. The values of foF2 and hmF2 recorded over Jicamarca (12°S; 77°W; dip lat. 1°N; mag. declination 0.3°) and sites of the conjugate point equatorial experiment (COPEX) campaign Boa Vista (2.8°N; 60.7°W; dip lat. 11.4°; mag. declination −13.1°), Cachimbo (9.5°S; 54.8°W; dip lat. −1.8°; mag. declination −15.5°), and Campo Grande (20.4°S; 54.6°W; dip lat. −11.1°; mag. declination −14.0°) have been used in this work. foF2 calculated by PARIM show good agreement with the observations, except during morning over Boa Vista and midnight-morning over Campo Grande. Some discrepancies were also found for the F-region peak height (hmF2) near the geomagnetic equator during times of F₃ layer occurrences. IRI has underestimated both foF2 and hmF2 over equatorial and low latitude sectors during evening-nighttimes, except for Jicamarca where foF2 values were overestimated.     

Advanced Pulsed Plasma Thrusters and Their Application as a Part of Small Spacecraft Propulsion Systems

The paper presents the research results of the effect of a capacitor energy storage device configuration on the specific characteristics of advanced modern propulsion systems based on the ablative pulsed plasma thrusters (APPT). These thrusters are designed to perform specific tasks within the small spacecrafts with the onboard power capacity up to 200 W.     

Remote upgrading of a space-borne instrument

The main purposes of experiment “Obstanovka” (“Environment” in Russian) consisting of several instruments are to measure a set of electromagnetic and plasma phenomena characterizing the space weather conditions, and to evaluate how such a big and highly energy consuming body as the International Space Station disturbs the surrounding plasma, and how the station itself is charged due to the operation of so many instruments, solar batteries, life supporting devices, etc. Two identical Langmuir electrostatic probes are included in the experiment “Obstanovka”. In this paper the Langmuir probes for “Obstanovka” experiment are described, including the choice of geometry (spherical or cylindrical), a more reliable method for the sweep voltage generation, an adaptive algorithm for the probe’s operation. Special attention is paid to the possibility for remote upgrading of the instrument from the ground using the standard communication channels.