Energy Stored leading to Dielectric breakdown

HPRF

1. The problem statement, all variables and given/known data

A cavity can only store 1J of EM energy as it reaches dielectric breakdown at 3kV/mm. What dielectric strength would a new gas filling the cavity have if the energy stored was to be 4J.


2. Relevant equations

U=[tex]\frac{1}{2}[/tex](epsilon)E²


3. The attempt at a solution

I would use the above equation to find the E field that would result in 4J of energy stored. Can anyone tell me if this is the correct approach to answering this question?

BertHickman

That's the correct approach. The energy scales as the E-field squared, so quadrupling the energy doubles the required E-field, so the gas dielectric must be able to withstand a field of 6 kV/mm without breaking down.