Modeling the time variation of beam–grid fusion reaction rates in an Inertial Electrostatic Confinement device driven by a ring-shaped magnetron ion source

Abstract

We use the two-dimensional analysis code KUAD2 to simulate D + 2 trajectories in an Inertial Electrostatic Confinement (IEC) device driven by a ring-shaped magnetron ion source (RS-MIS). This aims to maximize the path length λ CX for ion-gas charge exchange by operating at just units of mPa D 2 gas pressures; however, under these conditions simulations reveal a surprisingly small path length for ion loss to the (Mo) cathode grid λ grid ∼ 30 cm λ CX . By developing an ad hoc model relating the time variation of cathode temperature and absorbed D 2 surface density, we use the simulated flux grid of ions striking the cathode grid to obtain the neutron production rate (NPR) arising from 'beamgrid' reactions. Results indicate that at units of mPa pressures, beam-grid NPR may dominate over the 'beam-gas' and 'beam-beam reactions,' providing a qualitative explanation for earlier experimental observations of time-varying NPR-dependence on cathode grid current and gas pressure.

Preliminary results of a miniature cylindrical inertial electrostatic confinement fusion device equipped with inductively coupled plasma generator

“…Figures 5 to figure 7 represent the various measured neutron production rate (NPR) at different operational voltages of 30 kV, 35 kV and 40 kV which are depicted as a function of cathode current at different pressure and radio frequency (RF) power. It is deduced that by increment of cathode current the NPR increases almost as linear function for each data set at a fixed pressure while the RF power was changeable, (figure 5 to figure 7), and these linearity is in agreement with other similar IEC neutron yield results performed by K. Masuda and co-workers Also J. Kipritidis and J. Khachan [10][11][12]15]. Furthermore, in pulsed mode of operation which the IEC current increased of the order Ampere range, the NPR still have linear relation with the cathode current [2].…”