Self-Organized Space Charge Structure Formations in DC Glow Discharge

Bose, Subhojit; Majumder, Jayanta; Paul, Manash Kumar

doi:10.1109/tps.2022.3159657

Cited by 2 publications

(12 citation statements)

References 28 publications

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“…The plasma potential is obtained from the first derivative of the shielded Langmuir probe I‐V trace as shown in Figure 4a. [ 12,23,24 ] The I‐V trace is concomitantly obtained using an ordinary Langmuir probe for the reliability of the measurements, as shown in Figure 4b in discharge regime I. The I‐V traces and the respective plasma parameters obtained using both probes are in close agreement, indicating an insignificant error in the probe measurements.…”

Section: Resultsmentioning

confidence: 84%

“…The H‐exponent is a self‐similar parameter that determines the long‐term correlation in the recorded time series. [ 8,10,12,33 ] Generally, 0.5 < H < 1 indicates the persistency of the signal, H = 0.5 indicates an uncorrelated process, while 0 < H < 0.5 indicates the anti‐persistence of the data series. To examine how far the data set reflects long‐term correlation, the whole signal is divided into non‐overlapping bins and the H‐coefficients are obtained for each bin, shown in Figure 9a for V A ˜ 340 V. The R/S analysis provides H = 0.61 for the time lags from 12 to 300 while H = 0.83 for time lags from 300 to 1100, which indicates the existence of long‐term memory in the time series, and the trend persists in the next blocks of the data set.…”

Section: Resultsmentioning

confidence: 99%

“…A Helmholtz coil generates a uniform magnetic field of ˜20 G during the experiment, as shown in Figure 1. [ 12 ] Plasma diagnostics consist of a cylindrical Langmuir probe of tungsten wire of diameter ˜ 0.5 mm and a length of ˜4 mm, immersed into the plasma. The floating potential variation is measured during small temperature variations at 2 cm away from the anode surface during different discharge regimes.…”

Section: Experimental Setup and Diagnosticsmentioning

confidence: 99%

“…[ 1–5 ] However, in almost all of these cases, an ambient cathode plasma was produced by filament within a certain gas pressure range, in the absence of a magnetic field as well as in the presence of a magnetic field. [ 6 – 9 ] Self‐organized criticality (SOC) behaviour was investigated earlier during Double Layer (DL) formations in various confinement devices, mostly near the electrodes, [ 8,10,12 ] owing to its vital importance in the investigation and understanding of complexities in space plasma and fusion plasmas. [ 13 – 15 ] The SOC indicates the existence of self‐similarity in the discharge states and helps in understanding the fractal dimensions during such a discharge regime.…”

Section: Introductionmentioning

confidence: 99%

“…The different discharge modes appear along with the different complex structure formations during the progressive variation of anode potential across a spherical metallic ball anode, placed inside a cylindrical metallic cavity, which is connected as a cathode. [ 12 ] Initially, intense concentric complex structures occur around the anode surface in the form of multiple potential structures (double layers). These multiple double layers gradually transform into distinct anode spots (fire spots) through the self‐organized behaviour of the discharge states during progressive variation of anode potential.…”

Section: Introductionmentioning

confidence: 99%

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Formation of multiple anodic fire spots inside an electrostatic cavity

Bose

Debnath

Paul

2022

Contributions to Plasma Physics

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Charged particles exhibit self‐organized behaviour during the discharge state transitions inside an electrostatic cavity, along with the energy redistribution in different coherent modes with progressive anode potential. Multiple sheath formations around the spherical metallic ball anode placed inside the cavity transit to intensely glowing multiple anode spot formations (fireballs) on the anode surface with progressive anode potential. The intensely glowing anode spots reorganize over the anode surface and multiply quickly on increasing the anode potential. The nonlinear analysis of the fluctuating discharge current reveals the presence of self‐organized criticality (SOC) during different states of discharge along with a strong memory effect within (10–104) time lags in every state of discharge. The multiple anode spots exhibit long‐range correlation in the absence of a magnetic field, indicating SOC behaviour. The present study investigates energy distribution among the coherent modes of discharge through the application of the Empirical Mode Decomposition technique. The analysis indicates that the introduction of a magnetic field results in the interchange of coherent modes carrying most of the energy during multiple spot formations. The present experimental configuration produces stable multiple coherent modes along with the evolution of anodic sheath layers in the absence and then in the presence of the magnetic field. Relating SOC with such discharge transitions may help to understand the relation between complex structure formations in plasma with nonlinear aspects of glow discharge, which is of vital importance in the investigation of complexities in space plasma.

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Section: Experimental Setup and Diagnosticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Formation of multiple anodic fire spots inside an electrostatic cavity

Bose

Debnath

Paul

2022

Contributions to Plasma Physics

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Self-organization in the avalanche, quench and dissipation of a molecular ultracold plasma

Marroquín,

Wang,

Allahverdian

et al. 2024

J. Plasma Phys.

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Spontaneous avalanche to plasma begins in the core of an ellipsoidal Rydberg gas of nitric oxide. Ambipolar expansion of NO $^+$ draws energy from avalanche-heated electrons. Then, cycles of long-range resonant electron transfer from Rydberg molecules to ions equalize their relative velocities. This sequence of steps gives rise to a remarkable mechanics of self-assembly, in which the kinetic energy of initially formed hot electrons and ions drives an observed separation of plasma volumes. These dynamics adiabatically sequester energy in a reservoir of mass transport, starting a process that anneals separating volumes to form an apparent glass of strongly coupled ions and electrons. Short-time electron spectroscopy provides experimental evidence for complete ionization. The long lifetime of this system, particularly its stability with respect to recombination and neutral dissociation, suggests that this transformation affords a robust state of arrested relaxation, far from thermal equilibrium. We see this most directly in the excitation spectrum of transitions to states in the initially selected Rydberg series, detected as the long-lived signal that survives a flight time of $500\ \mathrm {\mu }$ s to reach an imaging detector. The initial density of electrons produced by prompt Penning ionization, which varies with the selected initial principal quantum number and density of the Rydberg gas, determines a balance between the rising density of ions and the falling density of Rydberg molecules. This Penning-regulated ion-Rydberg molecule balance appears necessary as a critical factor in achieving the long ultracold plasma lifetime to produce spectral features detected after very long delays.

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Self-Organized Space Charge Structure Formations in DC Glow Discharge

Cited by 2 publications

References 28 publications

Formation of multiple anodic fire spots inside an electrostatic cavity

Formation of multiple anodic fire spots inside an electrostatic cavity

Self-organization in the avalanche, quench and dissipation of a molecular ultracold plasma

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