Channel length and wall recombination effects in the Hall thruster

The Role of Magnetic Field Topography in Improving the Performance of a High Voltage Hall Thruster

“…Studies of channel length dependence have been hindered in the past because they usually did not change the magnetic field gradient along the length of the channel or the gas distributor. [25][26] So long as the magnetic field is properly modified, the real challenge of a short channel is maintaining uniform flow distribution. Apparently, these difficulties have been largely overcome in the BPT-4000, which employs a channel width to length ratio of 2:1.…”

Evaluation of Magnesium as a Hall Thruster Propellant

“…The relations in equations (10) and (11) indicate there are several control parameters in the design of a Hall thruster discharge channel: (1) electron temperature-controlled through discharge potential and channel dimensions [60,61], (2) thickness and location of ionization/acceleration region-controlled by channel dimensions [61][62][63][64], magnetic field topology and discharge potential [40], and neutral flow rate [65,66]. The biggest implication of equation 11is that different propellants may require physically different thruster dimensions to achieve the same efficiencies at the same operating parameter.…”

“…A longer and thinner channel would enact multiple benefits. A longer channel has been shown to collimate the plasma beam and as well as increase ionization efficiency [63] though any lengthening of the channel must be balanced with the increased ion losses to the wall [62]. Lowering the electron temperature could be achieved by reducing the channel width which may increase ionization rates for the magnesium plasma [61] but needs to be balanced by the increased wall losses due to interception of ions.…”

“…But, in addition to the ionization mean free path, the propellant utilization efficiency also depends on the number of ions lost to the discharge chamber walls. Cohen-Zur et al performed a study in which theoretical analysis of propellant utilization was investigated[62]. In their study, Cohen-Zur et alsolved the fluid continuity equations at the exit plane of the thruster in order to approximate propellant utilization as a function of the ionization mean free path, i , and the mean free path for ion loss to the channel wall, w .…”