Nov 17, 2008 · For a three-grid system, many of the charge-exchange ions created downstream of the grid plane will impact the decel grid at relatively low energies ( ~25 V), instead of impacting the accel grid at high energies ( ~200 V), thus reducing overall erosion.

The XIPS ion thruster uses a third molybdenum decelerator grid (“decel grid”), in addition to screen and accel molybdenum grids. To predict the long-term life and performance of the XIPS thruster, we must understand how the decel grid affects the erosion of the accel grid. Reference 3 discusses that the decel grid reduces ion current to

There are many factors that determine the grid design in ion thrusters. The grids must extract the ions from the discharge plasma and focus them through the downstream accelerator grid (accel grid) and decelerator grid (decel grid) (if used).

on accel and decel grid erosion 5. We modeled the single aperture of the extraction grid system and the adjacent plasma in 2D cylindrical axisymmetry . The code is based on a Particle In Cell with Monte Carlo Collision (PIC -MCC ) method for ions and the fluid approach for electrons. The calculation model

Aug 1, 2018 · For three-grid accelerator systems, a final grid called “decel grid” is placed downstream of accel grid. This grid shields the accel grid from ion bombardment by charge-exchanged ions produced in the beam from backflowing toward the thruster, and mitigates the downstream “pits-and-grooves erosion”.

A grid lifetime model is presented for the lifetime estimation of a 3-grid ion engine system. The failure mechanism considered in the model is electron backstreaming due to charge exchange ion erosion, which is fatal to the operation of the ion engine.

Sep 4, 2008 · Fig. 4 compares the grid masses for the screen, accel, and decel grids. As expected from Fig. 3 , the accel grid mass decreases rapidly by erosion, while the screen grid mass increases gradually due to redeposition.

May 7, 2019 · Results show that the decelerator grid has no effect on the focusing state and the distribution of beam ions. It also has little effect on the CEX ions from the upstream and extraction (center) regions. However, it has great influence on the downstream CEX ions.

The 4-grid system allows the ion extraction and ion acceleration processes to be decoupled, essentially creating a dual-stage system instead of the usual three grid thrusters where the two processes must occur simultaneously, leading to a practical limitation in the maximum beam potential to <5 kV. In the first stage

Dec 29, 2020 · Two-dimensional simulations tracked the time-dependent grid geometry and calculated changes in the electron backstreaming limit 𝑉 E B S V EBS as the grids eroded. Sensitivity studies assessed the impact of uncertainty in the operating screen-to-accelerator grid gap on 𝑉 E B S V EBS.