Pulsed power is the science and technology of accumulating energy over a relatively long period of time and releasing it instantly, thus increasing the instantaneous power.
The stored energy is released over a very short time scale resulting in a large amount of power being delivered to a load which can be used to study high energy density physics phenomena such as Inertial confinement fusion using a Z-pinch, and plasma physics or to create Electromagnetic radiation.
Other circuit architectures such as Linear transformer drivers or impedance-matched Marx generators typically do not require any pulse compression.
Single pulse energies as high as 100 MJ, power as high as a "few hundred terawatts" with voltages between 10 kV and 50 MV, and currents between 1 kA and 10 MA, have been achieved at least as of 2006.
[1] Railgun is one of the example usage of pulsed power and it is still at research stage due to its complexity.