Experimentation

From SpaceWeather

Introduction

In order to build the satellite, it was found that it was necessary to characterize lightning. Experiments that determine the peak voltage at measured distances are underway. The peak voltages must be determined in order to protect the system from overload. By establishing a relationship between lightning distance and peak voltage, precautions can be taken in order to protect the system.

Lightning Modeling Techniques

Lightning is an extremely difficult phenomena to model. In order to mimic the impulse created by lightning, various techniques were created. One simple technique used was sparking a cattle prod on a chair. The cattle prod, a Springer Magrath model, was used to model the impulse created by a lightning strike. However, after repeated testing, it was found that the cattle prod did not provide a constant electric potential every time. This led to errors in the data and no conclusions could be made with any degree of certainty. In order to build a constant voltage source, it was found necessary to build a Marx Generator. An explanation follows.

The Marx Generator

A Marx Generator is a basic circuit that consists of a voltage source, resistors, capacitors, and spark gaps. The Marx Generator takes an input voltage V and outputs a voltage that it equal to the input voltage times the number of capacitors in the circuit. The capacitors are charge in parallel by the resistors, effectively charging the capacitor to the input voltage. When the first spark gap breaks down (sparks), the voltage increases in the next spark gap. This process continues until all spark gaps break down. At this point, the low impedance of the ionized air in the sparks connects the capacitors in series. An arc is then created at is seen at the end of the circuit.