Atomic Physics

Paschen Curves for a Simulated Martian Atmosphere

 
We are trying to better understand the physics of electrical discharges in simple atmospheres. To do so, we have designed and built a vacuum chamber to house various electrode configurations that allow us to measure so-called Paschen curves. These curves display a gas's electrical breakdown voltage as a function of gas pressure and electrode geometry. Such data often reveal a feature called a Paschen minimum that indicates the conditions for which a discharge is most likely to occur.

Our first experiments involve single gas species; but we plan to investigate more complicated atmospheric conditions, such as those found on Mars. We are also developing computer simulations to help us better understand our laboratory results. NASA is interested in studies like this because the circuitry onboard Mars landers, for example, can be damaged if voltages between neighboring electronic components exceed specific values and create sparks. The nature of these sparks in different gaseous environments thus dictates the construction and operating parameters of the circuits.