Diagnostic techniques provide three-dimensional hydrodynamics of seawater hydrogen extraction

Given hydrogen power’s potential for abundant energy, extracting it through pulsed electrical currents in highly conductive seawater has garnered increased attention. Despite more than a century of investigation, much about the dynamics of underwater electrical pulses remains unclear, including how water’s role as a resistor shunting electrical charge between electrodes breaks down and leads to plasma generation.

Researchers have provided new diagnostics to characterize how capacitor discharges can efficiently heat seawater between submerged electrodes. Combining electrical, spectral, and laser probing techniques, Sarkisov et al. reconstruct the local seawater temperature distributions between the electrodes in three dimensions.

The work marks one of the first efforts to describe the relationship between electricity, temperature, and plasma formation in seawater discharge.

“Efficient extraction of hydrogen from water is important because it provides a virtually unlimited source of ecological energy on our planet,” said author Gennady Sarkisov. “Our wide range of diagnostic methods allows us to deeply penetrate into the physics of the interaction of pulsed current with water.”

At approximately one to three kilovolts, the discharging capacitors demonstrated purely resistive behavior without plasma generation. Increasing the voltage led to the formation of cathode plasma without shunting breakdown.

Further increasing to 6.5 kilovolts produced a plasma channel and shock waves that corresponded with voltage breakdown and light emission. The resulting temperature rise caused multiple local explosions related to the rapid growth of microbubbles over 2.5 microseconds.

The group looks to further study the interaction between water and electrical current, including using the Faraday effect.

Source: “Effect of electrical discharge in seawater,” by G. S. Sarkisov, D. Cooperstock, I. Blesener, P. Duselis, and M. Grange, Journal of Applied Physics (2025). The article can be accessed at https://doi.org/10.1063/5.0288747 .