"The manner in which we generate fusion-grade plasmas within our devices is fundamentally different from other existing fusion technologies. Hence, the publication of this paper will provide a crucial foundation for tracking our ongoing progress," says Uri Shumlak, co-founder and Chief Science Officer at Zap Energy, who is also the lead author of the paper.
As with other fusion energy devices, Zap Energy's mission is to fuse hydrogen nuclei within a material known as plasma. To achieve this, the plasma must be superheated to temperatures exceeding those of the sun. The plasma's properties can then be measured to determine Q, or net energy gain. This is calculated by evaluating the plasma's 'triple product': how hot the plasma is, how dense it is, and how long it lasts.
The concept of the triple product is particularly helpful when comparing different fusion methods. For example, it can elucidate how Zap's sheared-flow-stabilized Z-pinch devices contrast with traditional fusion devices such as the tokamak, or other fusion methods. Moreover, the triple product can act as a simplified proxy for Q.
One of the standout features of Zap's approach is the extraordinary density of its Z-pinch plasmas-about 100,000 times more dense than those found in conventional tokamaks-and their ability to last for numerous microseconds. The company is designing a pulsed system that would create these plasmas repeatedly, allowing for more sustained fusion reactions.
Zap's plasmas flow in a line, with materials at varying distances from the innermost part of the line moving at different speeds. This phenomenon, known as sheared-flow stabilization, helps to maintain the plasma long enough for sustained fusion reactions to take place. This technique allows Zap to confine plasmas without the use of external magnets, but it also necessitates distinctively suited measurements and analyses.
In order to calculate the triple product, Zap Energy measures the temperature of the plasma, its density, and the flow velocity, which helps determine the duration of plasma confinement. The resulting calculation of Q is a ratio of fusion power output to input power, which aligns closely with the method used to measure gain in other magnetic confinement approaches, such as the tokamak.
"Releasing these technical specifics is of paramount importance. You simply can't drop a thermometer into a fusion plasma to ascertain its conditions. Therefore, we rely on a combination of direct and indirect observations to get a picture of the situation," explains Ben Levitt, Zap Energy's Vice President of R and D.
The study also delves into a number of intricate details specific to Zap's fusion approach, one of the most critical being the consideration of the input power needed to drive the stabilizing plasma flow. The research also hints that for high performance pinches, it's likely that alpha particles-energetic by-products of the fusion reactions-will get trapped and boost fusion gain by offsetting some of the necessary input power.
Presently, Zap Energy is conducting research and development campaigns using its fourth-generation device, FuZE-Q, which achieved its first plasma last May. As the team advances towards demonstrating the first sheared-flow-stabilized Z-pinch plasmas capable of Q>1, they will scrutinize results from both FuZE-Q and its predecessor FuZE.
Related Links
Zap Energy
Powering The World in the 21st Century at Energy-Daily.com
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
