Studies on virtual electrode and ion sheath characteristics in a cylindrical inertial electrostatic confinement fusion device

Bhattacharjee, D.; Jigdung, D.; Buzarbaruah, N.; Mohanty, S. R.; Bailung, Heremba

doi:10.1063/1.5107471

Cited by 11 publications

(5 citation statements)

References 26 publications

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“…Similarly, for −5 kV applied potential, the drop is about 20% in the simulated profile and 44% in the experimental one. During −5 kV cathode voltage, a clear formation of a virtual cathode has been observed experimentally inside the cathode grid [33], while in the simulated result [Fig. 5(d)], only a slight indication of the virtual cathode is observed at the center.…”

Section: A Potential and Ion Density Profilesmentioning

confidence: 80%

“…After reaching the steady state in the simulation, the obtained potential profiles are plotted for better analysis. The equatorial plots of the potential profiles for different cathode voltages are compared with the experimentally established results [33], as shown in Fig. (5).…”

Section: A Potential and Ion Density Profilesmentioning

confidence: 99%

“…The potential at different positions inside the chamber is measured from the Langmuir probe. We varied the applied cathode voltage from −1 to −5 kV to observe the modifications in potential profile structure inside the cathode region [33]. To measure the plasma temperature and hence the ion density, we used a double Langmuir probe.…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

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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: A Potential and Ion Density Profilesmentioning

confidence: 80%

Section: A Potential and Ion Density Profilesmentioning

confidence: 99%

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

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Kinetic characteristics of ions in an inertial electrostatic confinement device

et al. 2020

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“…Current-voltage (I p − V p ) characteristics of emissive probes (EPs), as well as floating potential versus emission level curves, are used routinely to determine plasma potential in a wide range of scenarios [1][2][3][4][5][6]. These devices can diagnose a broad variety of plasmas, ranging from laboratory to space plasmas, and are present in several applications like electric propulsion testing [7] and non-magnetic [8,9] and magnetic fusion [10,11]. The theory of EPs is also a cornerstone in the modeling of space electrodynamic tethers coated with low work-function materials [12,13].…”

Section: Introductionmentioning

confidence: 99%

Parametrization of current–voltage characteristics and operation domains of cylindrical emissive probes in collisionless Maxwellian plasmas at rest

Shahsavani

Chen

Sánchez‐Arriaga

2021

Plasma Phys. Control. Fusion

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Important progress has recently been made on the Orbital Motion Theory for cylindrical emissive probes immersed at rest in collisionless and Maxwellian plasmas. However, due to the computational cost of its numerical algorithm, only solutions for specific values of the physical parameters were found, thus preventing its direct application to the interpretation of experimental current-voltage characteristics (I p − V p curves). In this work, and thanks to an analytical analysis of a Jacobian matrix appearing in the algorithm, the computational cost was reduced by a factor in the order of N r , where N r is the number of grid points. This achievement, together with the implementation of parallel programming, allowed to construct a database with more than 18,000 I p − V p curves for a broad range of physical parameters, including the emission level, the probe radius-to-Debye length, and the ion-toelectron temperature ratios. The boundaries in parameter space of the operational regimes of emissive probes, covering both orbital motion limited (OML) and space charge limited (SCL) transitions were computed. A novel OML/non-OML transition for emissive probes operating at low bias was found. The numerical results were used to propose useful analytical laws for the SCL boundary happening at negative bias, the reduction of the emitted electron current due to SCL effects, and the floating potential of emissive probes. The applications of the results to the modeling of low work function tethers and three experimental methods for measuring the plasma potential, i.e. the separation point, the inflection point, and the floating potential techniques, were discussed. The formation of an inverse sheath for strong emission was investigated.

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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%