arXiv subjects

Mikhail E. Viktorov

Publications and source records attributed to Mikhail E. Viktorov.

4 recordsLinked to original sources

arXiv2025

Surface Ion-Sound Wave in Magnetic Arch With High Pressure Plasma

The work analytically substantiates the parameters of the surface wave found in numerical modelling of the collision of two oncoming supersonic plasma flows inside a magnetic arc in application to the experiment on the laboratory setup ``Solar Wind'' (Inst. Appl. Phys RAS). An ion-acoustic surface wave exists in the regime of dense plasma flows when their dynamic pressure is of the order of the pressure of an undisturbed magnetic field, so that the flows push the initial magnetic field out of their volume. The wave frequency is in the range between the ion gyrofrequencies inside the plasma bundle and in the outer region of the confining magnetic field. In the external rarefied medium, the near-surface structure is a heterogeneous magnetic sound, consistent in pressure and low total polarisation of the medium with the ``isotropic'' ion sound confined from the inside in a dense plasma bundle. The energy of the structure is mainly contained in the kinetic energy of the wave motion of ions inside the tube. At the same time, the electric field strength is sharply increased outside. Firstly, the latter circumstance arises from the need to maintain a uniform electron electric drift velocity inside the transition layer. Secondly, the energetically weak ion sound propagating into the outer environment is close to electrostatic ion oscillations below the ion gyrofrequency in the external region, which are characterised by increased electric field strength across the ambient magnetic field.

physics.plasm-ph↗

arXiv2025

Influence of finite ion Larmor radius on the dynamics of weakly-collisional plasma jets colliding in magnetic arch

The effect of the finite ion Larmor radius on the dynamics of two counterstreaming weakly collisional plasma flows in a magnetic field of an arch configuration is considered. Hybrid numerical simulations show that in a system whose dimensions are close to the ion Larmor radius, more intense interaction dynamics are observed, the magnetic arch experiences a significant expansion with the formation of a region with an irregular character of magnetic lines, in which magnetic reconnection processes occur. In this case, the generation of a surface wave of the ion-cyclotron range is observed at the boundaries of the arch. An increase in the scale of the system compared to the ion Larmor radius leads to a transition to the ideal MHD regime, in which the evolution of the arch occurs much more slowly, and the development of instabilities is not observed.

physics.plasm-ph↗

arXiv2024

Numerical modeling of two magnetized counter-propagating weakly collisional plasma flows in arch configuration

Numerical modeling of the interaction process of two counter-streaming supersonic plasma flows with an arched magnetic field configuration in the regime of a magnetic Mach number of the order of unity $M_m \sim 1$ is carried out. The flows were launched from the bases of the arch along the direction of the magnetic field. It is shown that the interaction has non-equilibrium and non-stationary nature. It is accompanied by an expansion of the resulting magnetic plasma arch due to $E \times B$ drift with the formation of a region with oppositely directed magnetic fields, in which magnetic reconnection is observed. In the subcritical regime Mm < 1 the reconnection process is slow, and in the overcritical one Mm > 1 it is more intense and leads to plasma turbulization. Filamentation of flows due to the development of Weibel instability, as well as excitation of surface waves near the ion-cyclotron frequency on the surface of the plasma tube are also observed. The modeling was carried out for the parameters of an experiment planned for the near future, which made it possible to formulate the conditions for observing the effects discovered in the modeling.

physics.plasm-ph↗

arXiv2024

Torsional Alfven Oscillation in the Regime of Firehose Instability as a Mechanism of Plasma Stratification in a Laboratory Experiment on Modeling a Coronal Arch

The compact laboratory stand ``Solar Wind'' (Inst. Appl. Phys. of Russ. Acad. Sci.) forms an arch structure of the coronal loop type, in which the plasma pressure varies from zero to values of the order of and above the magnetic pressure. The arc discharge in each of the bases of the magnetic tube creates a plasma that is characterized by a significantly higher ion temperature along the magnetic field line than across the latter one. In the stationary state (when the ion pressure is below the threshold value for rupture of the system at the top of the loop), the plasma is found to be stratified in the form of a cylindrical layer along the outer wall of the tube or possibly two belts along the upper and lower vaults of the arch. The paper discusses the excitation of a torsional Alfven oscillation in the loop in the regime of firehose instability. In the case of rapid growth (with an increment of the order of an ion cyclotron period), the unstable Alfven oscillation essentially reallocates the particles between the central axis and the tube wall, which manifests itself in the form of the observed cylindrical layer.

physics.plasm-ph↗