Development of a long-slot microwave plasma source

Area of Science:

• Plasma Physics
• Microwave Engineering

Background:

• Microwave plasma sources are crucial for various applications.
• Controlling plasma properties like density and temperature is essential for optimizing performance.
• Homogeneous plasma distribution is often desired but challenging to achieve.

Purpose of the Study:

• To design and characterize a microwave plasma source with tunable plasma distributions.
• To investigate the effect of magnetic field arrangements on plasma uniformity.
• To measure plasma parameters downstream of the source.

Main Methods:

• A 20 cm microwave plasma source was constructed using two rod antennas.
• Permanent magnets were used to create adjustable magnetic fields, influencing plasma luminous distributions.
• Langmuir probe arrays measured electron density and temperature at 20 cm downstream.
• Microwave frequency was 2.45 GHz, and input power was 150 W.

Main Results:

• Plasma luminous distributions were successfully altered by magnetic field configurations.
• Homogeneous plasma distribution along the antenna was achieved at a specific antenna-to-wall spacing (7.5 mm).
• Measured electron densities ranged from 3.0 × 10^9 to 5.8 × 10^9 cm^-3.
• Measured electron temperatures ranged from 1.1 eV to 2.1 eV.

Conclusions:

• The developed microwave plasma source offers control over plasma uniformity through magnetic field manipulation.
• The findings provide insights into optimizing plasma parameters for specific applications.
• This work contributes to the advancement of controllable microwave plasma generation.