Study on discharge plasma in a cylindrical inertial electrostatic confinement fusion device

Buzarbaruah, N.; Dutta, Nirupam; Borgohain, Dima Rani; Mohanty, S. R.; Bailung, Heremba

doi:10.1016/j.physleta.2017.05.029

Cited by 22 publications

(5 citation statements)

References 18 publications

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“…The potential structure and ion density plays an important role for the occurrence of a fusion reaction [12] (during higher voltage operations) in such devices; a detailed study of these profiles during lower cathode voltage conditions become equally important for a complete understanding of the underlying physics of the IECF scheme. In this work, we have studied the behavior of a potential well and ion density profiles in the gas discharge plasma [28,30,31] during a relatively lower cathode potential (up to −5 kV), in both 8 and 16 gridded system (see Sec. II for details), using the XOOPIC code [32] (X11-based object-oriented particle-in-cell).…”

Section: Introductionmentioning

confidence: 99%

Kinetic characteristics of ions in an inertial electrostatic confinement device

et al. 2020

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The kinetic analyses are quite important when it comes to understanding the particle behavior in any device as they start to deviate from a continuum nature. In the present study, kinetic simulations are performed using the particle-in-cell method to analyze the behavior of ions inside a cylindrical inertial electrostatic confinement fusion (IECF) device which is being developed as a tabletop neutron source. Here, the lighter ions, like deuterium, are accelerated by applying an electrostatic field between the chamber wall (anode) and the cathode (cylindrical gridded wire), placed at the center of the device. The plasma potential profiles obtained from the simulated results indicate the formation of multiple potential well structures inside the cathode grid depending upon the applied cathode potential (from −1 to −5 kV). The ion density at the core region of the device is found to be of the order of 10 16 m −3 , which closely resembles the experimental observations. Spatial variation of ion energy distribution function has been measured in order to observe the characteristics of ions at different cathode voltages. Finally, the simulated results are compared and found to be in good agreement with the experimental profiles. The present analysis can serve as a reference guide to optimize the technological parameters of the discharge process in IECF devices.

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Section: Introductionmentioning

confidence: 99%

Kinetic characteristics of ions in an inertial electrostatic confinement device

et al. 2020

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“…To investigate processes occurring in the beam mode discharge, we compare principal characteristics of the emission spectrum observed for different modes in helium with general features of the cross section structure for excitation by electrons, ions and neutrals. We also examine the spatial distribution of emission, in which radial spoke-like lines pass through the electrode apertures, resembling the characteristic appearance of the 'star' mode discharge reported for many other spherical and cylindrical IEC devices [8,10,18,22,28,42,43]. We are interested in how this distribution is determined by our electrode configuration, which is unusual for an IEC set-up in having a relatively short, open-ended cathode grid surrounded by a relatively closelyspaced anode grid, with apertures of each arranged in radial alignment.…”

Section: Introductionmentioning

confidence: 83%

“…Glow discharges in which ions and neutrals are significantly energetic are relatively uncommon, and have mostly been studied in IEC for non-power fusion applications. Early IEC work was conducted at lower pressures [3][4][5][6], but since a simple discharge source was developed at the University of Illinois in the 1990s [7][8][9][10][11] research has been directed towards better understanding and improving the efficiency of benchtop fusion devices [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], since near-term applications increase with performance. These generally use a spherical or cylindrical hollow wire-grid cathode, operated either as self-sustained 'transparent cathode' discharge (TCD) or with an ionisation source.…”

Section: Introductionmentioning

confidence: 99%

Optical emission from a ‘beam mode’ transparent cathode glow discharge

Hardiment

Bowden

2021

Plasma Sources Sci. Technol.

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We investigate optical emission from a low-pressure ‘beam mode’ inertial electrostatic confinement glow discharge, created using cylindrical grid electrodes, having cathode inside a grounded, concentric anode. Spectral line distributions were measured in helium from this and a hollow cathode mode, with four lines emitted from singlet and triplet states with n = 3 and L = P and D compared against simple models for impact excitation by electrons and by ions and neutrals, suggesting much beam mode emission is caused by fast neutrals, and a significant component also caused by electrons. Beam mode emission occurs in a pattern of radial lines, that pass through aligned electrode apertures and extend across the chamber. Shadows cast by the electrode wires indicate electrically-neutral, beam-like sources of excitation, that cross the electrode assembly from bright radial lines in the opposing inter-electrode space, and calculated potential distributions show lensing surfaces around the anode grid apertures, focussing for inward-drifting ions. These indicate the emission pattern is caused by radially-convergent ion beams, and co-linear beams of fast neutrals produced in these. Emission was also observed with various alterations made to the electrode arrangement: with the anode removed, no beams were observed; with the cathode apertures rotated out of phase with those of the anode, bright radial beams between the electrodes followed the distribution of anode apertures; similar beams appeared with the grid cathode replaced by a solid version. In these experiments, progressive obstruction of pathways through the cathode caused increasing reduction in the beam pattern of emission beyond the anode radius, and in discharge perveance at similar pressure and voltage. Beam-like emission was also observed for a parallel-planar configuration, in which a cathode grid was held between two identical anode grids. The beam mode is shown to be a convergent, anode-focussed ion beam discharge, distinct to the star mode described elsewhere.

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“…Since the development of the very first IECF device 11,12 , the researchers carried out geometrical and technical modification of the device in order to increase the neutron yield [13][14][15][16][17][18] , over the years. Recently, our team of researchers at CPP-IPR have a) Also at:Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra, 400094, India; Email:smruti@cppipr.res.in carried out experiments in the cylindrical IECF device with some success in neutron production and its application in explosive detection [19][20][21][22][23] .…”

Section: Introductionmentioning

confidence: 99%