Electrode Shape Design for

Uniform Glow Discharge

Confinement

Wendy Figueroa1, Clarianne Moscoso11Commonwealth High School

Introduction

Plasma consists of an ionized gas into which sufficient energy is applied to free the electrons from their atoms.

Glow Discharge is a plasma formed by the passage of current through a gas at low pressure.

Objective

To determine the best shape in which to harness uniform plasma.

Method

Molded stainless steel into three different shapes:PyramidCubeAtom

Placed shapes in a closed, low pressure system.

Added high voltage.

Experimental Variables

Independent Variables

Dependent Variables

Controlled Variables

Voltage Plasma Nitrogen Gas

Pressure

Observations

In all of the shapes, the discharge points occurred near the welding points.

Glow discharge was concentrated on the center of the shapes.

As the voltage increased, the glow discharge increased

Data: Pyramid

We began with a fixed pressure of 9x10-3 Torr Nitrogen gas.

Voltage Observation

600 volts Glow discharge began

640 volts Began to flash

650 volts - 670 volts Glow discharge increased at points

Data: Cube

Voltage Observation

500 volts Glow discharge began

We began with a fixed pressure of 9x10-3 Torr Nitrogen gas.

Data: Atom

Voltage Observation

570 volts Faint glow discharge began

1,000 volts Electrical discharges increased

2,000 volts Plasma concentrated on the center

We began with a fixed pressure of 9x10-3 Torr Nitrogen gas.

Results

The cube, is the shape that best harnessed plasma because it was the shape that least required energy.

Conclusion

We were able to get close to our purpose.

As the voltage increases the glow discharge increases.

We found that the cube is the most efficient shape, due to its minimal need of energy ( only 500 volts).

Future Works

We believe that we could use less energy to harness plasma, by making a shape with more volume and less welding points.