Experimental study of plasma compression into the sheet in three-dimensional magnetic fields with singular X lines

Abstract

The formation and evolution of the plasma sheets resulting from the plasma compression in diversified three-dimensional (3D) magnetic configurations with singular X lines are reported on. The research was focused on the correlation between the structure of a plasma sheet and the topology of the initial 3D magnetic configuration, especially on the impact of the guide field aligned with the X line. It has been demonstrated experimentally that plasma compression and formation of extended plasma sheets can take place in configurations with the X lines in the presence of a strong guide field. The electron density distributions in the plasma sheets were found to be rather sensitive to the magnetic field topology. The experiments revealed the effect of progressive decrease of the plasma compression ratio in response to increasing guide field. This effect has two basic manifestations: a decrease of the maximum plasma density and an enlargement of the sheet thickness. Based on the experimental data we advanced a concept that the deterioration of plasma compression into the sheet is due to enhancement of the guide field inside the sheet over its initial value, and due to excitation of additional currents in the plane perpendicular to the singular X line and to the original current in the sheet.

Flow of a two-fluid plasma carrying a pulsed current in a steady-state magnetic field

“…The smaller the ion mass in the plasma, the faster the decrease in the slope of the trajectory with time. The calculation results agree well with the data of our experiments [1][2][3][4][5][6][7] on studying the current sheets in 3D magnetic fields with an X line and support the necessity of taking into account the two-fluid properties of plasma when current sheets form in heavy inert gases. …”

Dynamics of current sheets underlying flare-type events in magnetized plasmas

“…¿××ÇÍÕËÄÐÑÇ ÔÉÂÕËÇ ÒÎÂÊÏÞ Ë ÖÄÇÎËÚÇÐËÇ ÇÈ ÒÎÑÕÐÑÔÕË Ä ÔÎÑÇ Ä 5 ë 10 ÓÂÊ, ÒÑ ÔÓÂÄÐÇÐËá Ô ÐÂÚÂÎßÐÑÌ ÒÎÑÕÐÑÔÕßá, ÕÂÍÉÇ ÏÑÉÇÕ ÒÓÑËÔØÑAEËÕß ÒÓË ÓÂÊÄËÕËË ÕÑÍÑÄÑÅÑ ÔÎÑâ Ä 3D-ÏÂÅÐËÕÐÑÏ ÒÑÎÇ Ä ÒÓË-ÔÖÕÔÕÄËË ÒÓÑAEÑÎßÐÑÌ ÍÑÏÒÑÐÇÐÕÞ B z , ÍÂÍ Ë Ä ÔÎÖÚÂÇ 2D-ÒÑÎâ [26]. ³ÒËÔÑÍ ÎËÕÇÓÂÕÖÓÞ…”

VINETA II: A linear magnetic reconnection experiment

“…This process takes place in the current sheet formed at the boundary between opposed magnetic fields and is thought to play an important role in space phenomena, such as solar flares 4 and at Earth's magnetosphere 5 , as well as in fusion experiments 6,7 . Despite intense research on the topic over the last decades and a vast quantity of information obtained through space observations 8,9 , numerical simulations 10,11 and experiments [12][13][14][15][16][17][18][19] , the underlying processes of magnetic reconnection are still not fully understood. For plasmas with high resistivity and small length scales, simple magneto-hydrondynamic (MHD) models give an adequate description of reconnection 4,20,21 .…”