Electric potential barriers in the magnetic nozzle.

Area of Science:

• Plasma Physics
• Aerospace Engineering
• Applied Electromagnetics

Background:

• Magnetic nozzles are essential components in electric propulsion, manufacturing, and material processing.
• Understanding ion confinement within magnetic nozzles is critical for optimizing performance.

Purpose of the Study:

• To investigate the overlooked physics of thermalized ion confinement at the magnetic nozzle throat.
• To identify and analyze the factors limiting the extent of the ion-confining potential barrier.

Main Methods:

• Utilizing fully kinetic planar-3V particle-in-cell (PIC) modeling and simulation.
• Quantitatively investigating the effects of ion-to-electron temperature ratio and magnetic inductive strength (B0).

Main Results:

• An electric potential barrier forms at the nozzle throat periphery, confining thermalized ions via electric force.
• Ion overshooting due to thermal energy and insufficient magnetic confinement leads to positive space charge accumulation, creating the barrier.
• The barrier's limited extent is attributed to the finite-electron Larmor radius (FELR) effect, ion thermal energy depletion, and short-circuiting.

Conclusions:

• The potential barrier acts as a crucial interface for transferring gas dynamic thrust to the magnetic nozzle and constraining ions.
• In high magnetic field regimes, the finite-ion Larmor radius (FILR) effect becomes more significant for plasma confinement than the FELR effect.