Ion Engine Grid Erosion Cross-Section (2D)

Beam Parameters

Beam current density J_b 1.50 mA/cm²

Accel grid voltage |V_a| 300 V

Propellant

Time acceleration 500 hr/s

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Live Readouts

Simulated run time

0 hr

Erosion depth

0.00 µm

Grid life used

0.0%

Est. remaining life

— hr

CEX impact energy

300 eV

Beam divergence

3.0°

Perveance / impingement risk

low — CEX erosion only

How this 2D cross-section differs from the 3D view

The 3D sim revolves one aperture into a full 3D scene and shows an erosion ring that only grows uniformly. This 2D companion instead draws the true axisymmetric r–z cross-section (radius vs. axial distance) through the screen and accel grid pair — the same kind of profile plot real grid-erosion studies (e.g. NSTAR/NEXT wear-testing) actually publish, because it shows the eroded shape, not just its overall size.

Perveance:      P = J_b / |V_a|^1.5
Sputter yield:  Y(E) = Y_max · [(E − E_th) / (E_ref − E_th)]^1.5,  0 ≤ Y ≤ Y_max
Erosion rate:   dh/dt ∝ (J_b/J_ref) · Y(|V_a|) · f_propellant · f_impingement(P)

Charge-exchange (CEX) erosion: slow ions born downstream of the accel grid get pulled back by its negative field and slam into the downstream lip of the accel aperture. Here that is drawn literally: the accel aperture's downstream corner grows an actual carved notch (the "pit-and-groove" profile) whose depth is driven by the same erosion-rate formula as the 3D sim, not by scaling a ring.

Perveance and direct impingement: push J_b/|V_a|^1.5 past its critical value and the beamlet can no longer be focused through the aperture — some beam ions now strike the accel grid's front face directly instead of passing through. This 2D view draws that as visible orange impact sparks on the accel plate face, in addition to the CEX groove, which the 3D scene does not distinguish visually.

Sputter yield & propellant: impact energy above threshold E_th knocks grid atoms loose, following a Bohdansky-type curve; krypton's lower atomic mass gives it a lower yield than xenon at the same energy.

Both the erosion-rate formula and every constant (J_ref, E_th, E_ref, the perveance threshold, the grid thickness limit) are the same order-of-magnitude illustrative values as the 3D sim, re-derived independently here rather than imported from it — a quick numeric check confirms they place the default operating point (1.5 mA/cm², 300 V) safely below critical perveance and give a multi-thousand-hour grid life, consistent with real NSTAR/NEXT wear-test lifetimes.

low risk

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Beam ions (through aperture) CEX ions (pulled back, erode rim) Direct impingement (high risk only) Grid plates