This paper describes the results of a laboratory experiment on the sub-Alfvén expansion of a quasi-spherical laser plasma cloud into a vacuum magnetic field in the regime of nonmagnetized ions. The role of Hall fields and currents in the anomalously fast dynamics of the magnetic field during the collapse phase of a diamagnetic cavity is considered. Detailed spatial measurements of the azimuthal Hall fields configuration are demonstrated and their relationship to diamagnetic cavity collapse is determined. As a result of the experiment, data were obtained confirming the hypothesis about the transfer of the main magnetic field by the movement of electrons associated with Hall currents.

В настоящей работе представлены результаты лабораторного эксперимента по разлету плазменного облака во внешнее магнитное поле, впервые демонстрирующего подавление характерных Холловских эффектов присутствием фоновой плазмы. Показано, что увеличение концентрации фоновой плазмы приводит к снижению величины Холловских магнитных полей и соответствующих токов, что, в свою очередь, изменяет характер протекания коллапса диамагнитной каверны. При подавлении Холловских эффектов динамика каверны протекает более плавным образом и задерживается по времени. Полученные данные не только обнаруживают влияние фоновой плазмы, но и подчеркивают взаимосвязь между Холловскими эффектами и аномально быстрой динамикой магнитного поля на фазе коллапса диамагнитной каверны.

The laboratory experiment on modeling a sub-Alfvénic interaction of expanding plasma cloud with vacuum magnetic field is described. We produce spherically symmetric cloud by 4-beam laser irradiation of the pellet. The presented data reveal complex dynamic of cloud deceleration and formation of two field aligned jets, development of the flute instability and rapid collapse of the diamagnetic cavity. It is shown that cavity collapse can’t be explained by plasma motion or anomalous diffusion and requires for explanation a new mechanism.

For the first time to solve the problems of laboratory modelling of cosmophysical phenomena of an explosive nature (active experiments of the AMPTE type, with barium injections into the magnetosphere), spherical laser plasma clouds (LPCs) were produced and applied (in experiments at the KI-1 test facility of the ILP SB RAS). Use was made of the classical four-beam scheme of irradiation (regular tetrahedron) of a polyethylene target ball (∅1 cm) by CO 2 laser radiation with an energy of up to 500 J. A high degree of symmetry of the expansion of a near-spherical LPC with a moderate velocity of ∼100 km s −1 and an energy of up to 30 J has been achieved. The regimes of deceleration and formation of the spherical-LPC diamagnetic cavity were modelled for the first time, as well as the development of flute instability during the expansion of barium clouds across the geomagnetic field and the dynamics of these clouds along the field.

We describe an experiment on the interaction of a dipolar magnetic field with the laser plasma flow produced inside of a laboratory magnetosphere. This interaction is found to exhibit two dynamic stages: after a prompt displacement of the dipole field by the laser plasma, the magnetic field is captured and carried outside of the magnetosphere. The resultant data confirm the results of previous measurements carried out far beyond the magnetosphere and provide additional information about the new process of capturing the dipolar magnetic field by the internal magnetospheric plasma flow.

An experiment to model a system of field-aligned currents in a dense inner magnetospheric plasma is performed under laboratory conditions for the first time. The magnitude and length of the flow of field-aligned currents were measured as a function of the magnetic field.

Today a number of various experiments with Laser-Produced Plasmas (LPP), done at very-high Magnetic Fields (up to B0 > MG) are using to model the physics of Astrophysical and Space Jets, a various processes of their formation and possible long-range propagation at various angles S to magnetic fields. We discuss the opportunity and present the first results of new-type experiments on simulation of Jets with LPP at KI-1 facility of ILP, at moderate magnetic field ∼ kGs, oriented quasi-transverse (S ≍ 600) of LPP-blob expansion (with velocity V 0) relative to B 0. They were done on the base of all our preliminary studies, both at large-scale, high-vacuum chamber (0120 cm of KI-1) and others devices with LPP (oriented earlier at V0 transverse to B0, with $ = 900).

The limiting mode of the generation of low-frequency torsional whistlers is obtained for the first time. Laser plasma clouds create only weak whistlers in a weakly magnetized laboratory plasma (argon), allowing the whistler magnetic field to reach record values of ~25% of the background magnetic field.

The paper presents the results of laboratory experiment modeling the interaction between Lunar magnetic anomalies and Solar wind. To model the LMA we use quadrupole magnetic field. The main dimensionless parameter of the problem, the ion inertia length relative to the mini-magnetosphere size, well corresponds between experiment and LMA conditions. The main result is measurement of the magnetically reflected proton fluxes, which show qualitative agreement to available satellite data.

On the base of NASA [1] new approach about important role of Giant plasma releases of so called Coronal Mass Ejections (CME, with kinetic energy up to Ei 10363pr) from the Sun, we have started a series of simulative experiments [2, 3] with Laser -produced Plasma (LP), expanding into magnetized Background Plasma (BP) to generate laboratory Quasi -Perpendicular collisionless Shocks (Q -PS) by LP -piston for the first time. As a result of such experimental scenario, with the I,P-model of CME and Q -PS as interplanetary Collisionless Shock Wave (CSW, observed ahead of super-Alfvenic CME), we did a first comparative study of a quasi -stationary model of magnetosphere (by BP, overflowing magnetic dipole 1.1.) with its compressed form after LP formation and following Q -PS generation in BP. During the first set [3] of such experiment MagnetoPause-Shock (MPS), we had measured a maximal additional (due to Q -PS) compression near twice of the total (and global quasi uniform) magnetic field Bi inside of MP. Here we could present and discuss some specific experimental features of these ft -fields and both their models and distributions. Additional attention was done to the important collisionless processes of the Q -PS generation, especially in the given case of the different mass (m/z) of ions in LP -piston. For the last purpose a new data on the dynamics of such ions (H"and C'n) were presented including data of 2D and 3D calculations by Hybrid models with PIC (Particles In Cells) description of all ions.

We report the results for the first complex experiment on the formation of an extended (up to similar to 0.5 m) plasma jet in a magnetic field (up to 300G) in vacuum. The jet appears due to the injection of laser plasma bunches with a kinetic energy up to similar to 50 J across the magnetic field (in a solid angle Omega approximate to 1 sr) and a high degree of magnetisation of ions on the calculated scale field-induced deceleration of the bunch as a part of a sphere. A plastic target (polyethylene) has been irradiated by a CO2 laser in the most energy-efficient regime (near the plasma formation threshold), implemented at the expense of a wide radiation spot (diameter 23 cm) on the target. In a new-type model Super-Jet experiment on a large KI-1 facility at the Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences (ILP SB RAS), the probe data on the internal structure and dynamics of plasma concentration and magnetic field strength in transverse jets, on the influence of instabilities and Hall effect have been obtained for the first time in laboratory modelling of space and astrophysical jets.

Combining such methods of plasma registration as spectral, probe and optical diagnostics, in this paper propagation of laser plasma in a vacuum magnetic field was studied. By means of Langmuir and magnetic probes such plasma parameters as velocity and the angle of expansion were measured, as well as the size of magnetic cavity. Using optical monochromator combined with CCD a Doppler broadening of a number of ionic and atomic lines was measured and the transversal speed of the plasma cloud expansion was calculated. The data plasma cloud propagation velocity and expansion angle obtained by two methods was compared with gated imaging data and magnetic probe measurements of cavity size.

Abstract It was shown for the first time that in a laboratory experiment a train of laser plasma clouds makes it possible to increase the length of the whistler waves generated in the power tube of a magnetized medium. The intensity of waves is orders of magnitude higher than the level achieved by known methods.

Whistler waves produced by periodic bunches of a laser plasma in a magnetized plasma are investigated. It is shown for the first time that a train of laser plasma bunches generates a packet of torsional whistlers, which contains a high-frequency front part and a quasi-stationary track localized in a power tube. The length of the track increases with the number of bunches, which allows you to control the spectrum of the waves and form low-frequency waves.

The absorption of stellar radiation observed by HD 209458b in the resonant lines of O I and C II has not yet been satisfactorily explained. We apply a 2D hydrodynamic multi-fluid model that self-consistently describes the expanding planetary wind, driven by stellar XUV radiation and influenced by tidal forces and the surrounding stellar wind. According to this model, HD 209458b has a hydrogen-dominated plasmasphere, expanding beyond the Roche lobe, in the form of two supersonic streams that propagate toward and away from the star. The species heavier than hydrogen and helium are dragged in the escaping material streams and accelerated up to 50 km s(-1). Our simulations show that, assuming solar abundances, O I and C II produce absorption due to the Doppler resonance mechanism at the level of 6%-10%, which is consistent with the observations. Most of this absorption takes place in the streams. The transit depth in the O I and C II lines is unaffected by the stellar wind, unless it is strong enough to form a compact bowshock around the planet and able to redirect all the escaping material to the tail. In this case, the absorption profile becomes asymmetric due to the prominent blueshifted attenuation. Thus, the spectroscopic measurements enable probing of the planetary wind character, as well as the strength of the stellar wind. The computed absorption at wavelengths of the Si III, Mg I, and Mg II lines at solar abundances appears to be much stronger, compared to the observations. This possibly indicates that Si and Mg may be under-abundant in the upper atmosphere of HD 209458b.

Hot Jupiters (HJ) are exoplanets, gas giants with low orbits (≤ 0.1 a.u.). The stellar X-ray and ultraviolet (XUV) radiation energy deposition result in heating ionization and the consequent expansion of planetary atmosphere. Expansion of upper atmosphere under certain conditions could be so large that the majority of light atmospheric constituents overcome the gravitational binding and escape from the planet in a form of hydrodynamic wind. Besides interaction of two counter-streaming plasma flows (stellar wind and ionized upper layers of planet atmosphere), each of this flows interact with planetary magnetic field. In such complex situation laboratory simulation can provide data that can’t be obtained by computer simulation or observation. Experiment was carried out on KI-1 facility: high-vacuum chamber 5m long, 1.2 m in diameter with pressure ∼ 10-6 Torr. Magnetic dipole with two attached laser targets played the role of a planet, and background plasma from θ-pinch used for simulation of stellar wind. As a result, data on a behavior of plasma density and magnetic field were obtained. The novel phenomenon was registered: magnetic field is transferred by the cloud of laser plasma, which was not observed before in experiments or calculations.

Dynamic interaction of super-sonic counter-streaming plasmas moving in dipole magnetic dipole is studied in laboratory experiment. First, a quasi-stationary flow is produced by plasma gun which forms a magnetosphere around the magnetic dipole. Second, explosive plasma expanding from inner dipole region outward is launch by laser beams focused at the surface of the dipole cover. Laser plasma is energetic enough to disrupt magnetic field and to sweep through the background plasma for large distances. Probe measurements showed that far from the initially formed magnetosphere laser plasma carries within itself a magnetic field of the same direction but order of magnitude larger in value than the vacuum dipole field at considered distances. Because no compression of magnetic field at the front of laser plasma was observed, the realized interaction is different from previous experiments and theoretical models of laser plasma expansion into uniform magnetized background. It was deduced based on the obtained data that laser plasma while expanding through inner magnetosphere picks up a magnetized shell formed by background plasma and carries it for large distances beyond previously existing magnetosphere.