Note: The expansion of possibilities for plasma probe diagnostics

Area of Science:

• Plasma Physics
• Ion Mass Spectrometry

Background:

• Low-pressure Maxwellian plasmas require accurate ion mass determination.
• The Bohm formula relates ion current density to plasma parameters, including ion mass.

Purpose of the Study:

• To determine the ion mass in low-pressure Maxwellian plasmas.
• To validate the applicability of the Bohm formula for ion mass determination.

Main Methods:

• Utilized Langmuir probe measurements.
• Employed the Bohm formula for ion current density calculations.
• Accurately measured xenon plasma parameters in an inductive discharge (p = 2 ⋅ 10⁻³ Torr).

Main Results:

• The Bohm effect was validated with engineering precision under experimental conditions.
• The experimental Bohm coefficient (CBCyl) for cylindrical probes was determined to be approximately 1.13.

Conclusions:

• Langmuir probe measurements combined with the Bohm formula provide a viable method for determining ion mass in low-pressure plasmas.
• The Bohm formula is applicable with high accuracy for cylindrical probes in the studied xenon plasma conditions.