What is voltage withstand, jacket spark of coaxial cable

When I'm having a look at coaxial cable spec:
...
Voltage withstand is 2KV
Voltage spark is 5KV
Peak power 16KW
...

1. What is the different between Voltage Withstand and Voltage Spark?
2. How to calculate peak power ?

Pls help me understand them.

Usual technical terms for cable specifaction are maximum operation voltage and test voltage. Breakdown voltage isn't usually specified but must be above test voltage, obviously.

Power handling is specified as CW power versus frequency and is mainly reflecting frequency dependant skin effect losses. "Peak power" will be respectively higher as long as the voltage rating is kept, but rarely specified. You would want to estimate it based on CW power ratings, peak duration and thermal time constants.