Current and light waveforms associated with the dark- to glow-discharge transition in medium- and low-pressure point-to-plane gaps

Abstract

In nitrogen, for pressures below 200 Torr, the anodic glow is characterized by current oscillations, superimposed on a dc component. These oscillations may be attributed to fluctuations of the space charge, structured as a double sign sheath (double layer). The transition from a dark to a glow discharge can occur either directly from the oscillating state or, in the 20-200 Torr pressure range, through the appearance of a particular regime characterized by recurrent impulses. Both cases are considered here in the case of pure nitrogen, and the influence of pressure and gap length on the current and light waveforms is studied. An analysis of the light emitted by the discharge shows that a luminous structure, formed in the anode region, propagates towards the cathode, and travels a few millimetres before being absorbed by the sheath structure. This may be interpreted as the beginning of an ionizing front, which cannot propagate and is choked by the double layer. For higher applied voltages, the double layer cannot be maintained, and the current limiting effect seems to be suppressed during the time for charge evacuation; the current and light impulses corresponding to this latter case are then integrated into the much larger ones which characterize the glow discharge.

Numerical study of active particles creation and evolution in a nitrogen point-to-plane afterglow discharge at low pressure

“…If the frequency of the applied voltage does not permit this relaxation, the discharge starts on a non-virgin gap with a non-neutral electrical background. All these results are coherent with experimental observations concerning the dark to glow discharges transition in medium and low pressure point-to-plane gaps, which has led also to the hypothesis of a DL formation [14,15].…”

“…The electric field is treated in a quasi-two-dimensional form by the classical 'disks' method [42]. This method implies an assumption on the radial profile of the discharge that, in our case, may be represented by a truncated cone [14,18,20], as has been already mentioned. The radii used in the present study are r c = 0.3 cm on the cathode side and r a = ρ = 0.05 cm on the anode side (ρ being the anode curvature radius).…”

“…This condition implies that the physical quantities are constant on any cross section of the discharge. Following several experimental results [14,15], the discharge presents an axial symmetry, so we assume that the latter condition is valid. For the pressure used in this work (4 Torr/1 cm of gap length) the discharge radius on the cathode side seems to be many times larger than the radius on the anode side [16,17].…”

Poling of Glasses Using Resistive Barrier Discharge Plasma

“…For higher voltages (1300 and 1500 V) passed charge monotonously increases, as expected. Note that after several minutes of poling, the light emission disappears, i.e., the discharge changes its type to the so-called “dark discharge” [ 29 ], though the current remains gradually decreasing. The fact that the poling carries on means that there is still plenty of hydrogen/hydronium ions in the environment of the specimen at this stage.…”

Energy Control of Capacity-Coupled Discharge in Atmospheric Air

“…This quenching time is close to that of DBD, e.g., 50 ns as reported by Gibalov and Pietsch, 16) 20 ns by Braun et al, 17) and 20 ns from light emitted from discharge plasma reported by Dong et al 18) In general, the streamer corona propagates with a velocity of 10 5 -10 6 m/s. [19][20][21][22] The streamer corona propagation time can be estimated to be 1 to 2 ns under our experimental conditions. After the streamer corona bridges between the electrodes, the ''cathode sheath'' is established within 1 to 5 ns.…”