1. Electrode Shape Design for Uniform Glow Discharge Confinement Wendy Figueroa 1, Clarianne Moscoso 1 1 Commonwealth High School

2. 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.

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

4. Method  Molded stainless steel into three different shapes:  Pyramid  Cube  Atom  Placed shapes in a closed, low pressure system.  Added high voltage.

5. Experimental Variables Independent VariablesDependent VariablesControlled Variables VoltagePlasmaNitrogen Gas Pressure

6. 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

7. Data: Pyramid  We began with a fixed pressure of 9x10 -3 Torr Nitrogen gas. VoltageObservation 600 voltsGlow discharge began 640 voltsBegan to flash 650 volts - 670 voltsGlow discharge increased at points

8. Data: Cube VoltageObservation 500 voltsGlow discharge began  We began with a fixed pressure of 9x10 -3 Torr Nitrogen gas.

9. Data: Atom VoltageObservation 570 voltsFaint glow discharge began 1,000 voltsElectrical discharges increased 2,000 voltsPlasma concentrated on the center  We began with a fixed pressure of 9x10 -3 Torr Nitrogen gas.

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

11. 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).

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