Schematic view of the 3D simulated geometry. From left to right, the ICP discharge (also called “driver”) couples the external power from RF coils (unsimulated) to the plasma; the next section is the expansion chamber which is magnetized. The magnetic field barrier is generated by a set of permanent magnets located on the lateral walls of the chamber. Field lines are outlined in blue. The dotted-dashed lines on the RHS wall are the so-called PG, which connects the ion source to the electrostatic accelerator.
2D profiles of the plasma potential are shown in the XY (Z = 0) and XZ (Y = 0) planes. Iso-potential lines are also displayed. The PG is biased at 20 V. The plasma asymmetry in the electron magnetic drift plane (Y = 0) is clearly visible.
Positive ion flux energy distribution functions (edf) on the PG for the three ion species, , and .
Charged particle density profiles on the ion source axis (Y = Z = 0).
Plasma potential profile on the ion source axis versus the PG bias voltage.
(a) Electron (Ie ) and total positive ion (I +) currents on PG versus bias. The negative ion current IH – also plotted corresponds only to negative ions produced by positive ion impact on the PG (i.e., negative ions generated by atomic hydrogen impact or returning to the PG are not included). (b)Average kinetic energy of the incident positive ions on PG.
Average positive ion kinetic energy on the ion source axis, . Profiles are shown from the middle of the driver up to 2cm from the PG. The potential gap in this region is and the PG bias is 20 V.
Positive ion means free paths (mfp). Total elastic, charge exchange, and inelastic collision mfp (solid lines) and destruction mfp (dashed-lines) are shown. The blue color corresponds to protons, black for and grey ions. The PG bias is set to 20 V.
Heavy particle processes.
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