Shock Waves of the Electric Field—Part 2: Experimental Studies of Vysikayl’s Jumps and Plasma Nozzles in Plasma With Current

In our works, we prove that the cumulation (self-focusing) of charged particles in a plasma (with current) is a universal property of cumulative-dissipative structures (CDSs) with characteristic sizes from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-15}$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{27}$ </tex-math></inline-formula> m. The basis of such cumulation is the self-formation of electric field shock waves. Earlier (in Part 1) we proved that the electric field (in a gas-discharge plasma with current) behaves as an additional (to the concentrations of charged particles) component of the plasma. Therefore, both drift profiles and diffusion jumps (sharper discontinuities) should be observed in the plasma, analogs of ordinary Mach shock waves or magnetic field shock waves described by Sagdeev. In electric field shock waves, the pressure is created by the electric field (E) pressure—<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\text {E}}\sim E^{2}$ </tex-math></inline-formula>/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\pi $ </tex-math></inline-formula>. Electric field shock waves were first predicted by the author in 1985. The author claims that these standing shock waves focus structures (in a plasma with current) by ambipolar drifts caused by the nonlinearity of the processes of transport of charged particles of the plasma. In this article, we will dwell in detail on the experimental studies of 3-D self-forming plasma cumulative-dissipative Vysikaylo’s structures in gas-discharge plasma. By comparison with experiments, we prove that it is necessary to take into account the violation of electrical neutrality (Poisson’s equation for the electric field) in gas-discharge plasma with current. In this part 2, we will use photographs and double probes to study the self-formation of inhomogeneous 3-D structures (plasmoids) due to the interference of ambipolar drift and gas pumping in inhomogeneous plasma using a local ionizer. For this purpose, we preliminarily locally disturbed the homogeneous plasma in the gas-discharge tube with a beam of fast electrons. This leads to self-formation of local: 1) shock waves of the electric field (a monolayer of positive space charge with jumps of the electric field), stopped by pumping gas (on one side of the fast electron beam); 2) transient 3-D profiles; and 3) Vysikaylo’s plasma nozzles in quasi-neutral homogeneous plasma (on the other side of the beam disturbing the plasma). Based on laboratory experiments and theoretical studies of gas-discharge plasma, we prove that the ambipolar drift caused by different dependences of the electron and positive ion mobility in a simple plasma (with one type of ions) determines the dynamic processes of cumulation (self-focusing) and the formation of 3-D shock waves of the electric field due to the violation of electrical neutrality in electropositive gases.