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Yushkov G.Y.,Institute of High Current Electronics | Anders A.,Lawrence Berkeley National Laboratory
IEEE Transactions on Plasma Science | Year: 2010

Repetitive pulses of voltage and current are applied in high-power impulse magnetron sputtering. The current pulse usually lags the applied voltage by a significant time, which, in some cases, can reach several tens of microseconds. The current time lag is generally highly reproducible and jitters less than 1% of the delay time. This work investigates the time lag experimentally and theoretically. The experiments include several different target and gas combinations, voltage and current amplitudes, gas pressures, pulse repetition rates, and pulse durations. It is shown that, in all cases, the inverse delay is approximately proportional to the applied voltage, where the proportionality factor depends on the combination of materials and the conditions selected. The proportionality factor contains the parameters of ionization and secondary-electron emission. The statistical time lag is negligible, while the formative time lag is large and usually dominated by ion motion (inertia), although, at a low pressure, the long free path of magnetized electrons causing ionization contributes to the delay. © 2006 IEEE.

Tarasenko V.F.,Institute of High Current Electronics
Plasma Physics Reports | Year: 2011

Conditions under which the number of runaway electrons in atmospheric-pressure air reaches ~5 × 1010 are determined. Recommendations for creating runaway electron accelerators are given. Methods for measuring the parameters of a supershort avalanche electron beam and X-ray pulses from gas-filled diodes, as well as the discharge current and gap voltage, are described. A technique for determining the instant of runaway electron generation with respect to the voltage pulse is proposed. It is shown that the reduction in the gap voltage and the decrease in the beam current coincide in time. The mechanism of intense electron beam generation in gas-filled diodes is analyzed. It is confirmed experimentally that, in optimal regimes, the number of electrons generated in atmospheric-pressure air with energies T > eUm, where Um is the maximum gap voltage, is relatively small. © 2011 Pleiades Publishing, Ltd.

Sorokin S.A.,Institute of High Current Electronics
Technical Physics | Year: 2011

Experimental data for creating an X-ray source several millimeters in size on the basis of a plasmafilled rod-pinch diode are reported. Experiments are carried out on the MIG high-current generator. A voltage pulse applied to the diode is sharpened and shortened by injecting plasma into the interelectrode gap up to the plasma-filled diode. Radiation extraction from the vacuum chamber in the paraxial direction is provided by inverting the positions of the cathode and anode using a post-hole vacuum convolute. It is demonstrated that the energy of a low-impedance high-current generator can be deposited with a high efficiency into an electron beam focused on the 1-mm2 tip of the rod-shaped anode. With a tapered tungsten rod 1.5 mm in diameter used as an anode, a pulsed X-ray source about 1 mm in size generating 30-ns-long pulses is obtained. The absorbed dose per pulse measured with a LiF thermoluminescent dosimeter behind a 5-mm-thick aluminum screen 1 m away from the source reaches 0.042 Gy. © 2011 Pleiades Publishing, Ltd.

Sorokin S.A.,Institute of High Current Electronics
IEEE Transactions on Plasma Science | Year: 2010

The MIG generator was used in a magnetic flux compression experiment to produce a high magnetic field inside a dielectric tube located along the axis of an imploding plasma liner. With a liner current of ∼1 MA and a tube diameter of 25 mm, magnetic fields of up to 60 T with a quasi-steady pulse duration of 100 ns and more were produced. The high magnetic field region is protected from the liner plasma and radiation by the tube wall, and it can be used to study the physical phenomena that occur in high and ultrahigh magnetic fields. The physical processes responsible for the evolution of the magnetic field in a dielectric tube are discussed. © 2010 IEEE.

Korolev Y.D.,Institute of High Current Electronics
Gaodianya Jishu/High Voltage Engineering | Year: 2013

The paper reviews the results of investigations of the low-current atmospheric-pressure discharges in gas flow. The attention is focused on the discharges in electrode systems of coaxial plasmatron and of so-called gliding arc. It is demonstrated that a considerable fraction of discharge current is carried by a plasma column operating in a regime of normal glow discharge with occasional transitions to spark. The nature of glow-to-spark transition is discussed. Beside the plasma column, a weakly ionized gas fills in the interelectrode gap and forms a plasma jet at the exit of electrode system. The jet contains the active chemical particles that play important role in different discharge applications. The applications in plasma assisted combustion systems, for surface treatment with a usage of plasma jet, and for biology and medicine are considered.

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