The Reverspark is the answer to the demand in non-wearing sparker tips..
The reverse polarity of that sparker catamaran has the advantage of improving the resolution of the reflected signal. The sparker signature is shortened, and the delay of the bubble collapse is reduced to nothing.
For no wear off, the tips of the sparker must be at the cathode. The Reverspark has the anode underneath the bottom board, protected from the surrounding by the catamaran structure. No need to be in negative polarity mode. The negative polarity mode is mandatory for the safe use of steel catamarans. It is the technical reason of that mode of discharge.
There is no current intensity difference between the reverse polarity and the negative polarity. The sharp pulse rise of the current makes a high dI/dt.