In a recent publication in Fusion Science and Technology, Zap Energy has presented its groundbreaking methodology for quantifying the net energy gain, denoted as Q, in sheared-flow-stabilized Z-pinch fusion plasmas. This achievement represents a significant milestone in the advancement of fusion energy development. Credit: Zap Energy
A newly published study by Zap Energy has outlined scientific techniques for the measurement and calculation of Q in sheared-flow-stabilized Z-pinch fusion plasmas. This unique approach sets Zap Energy apart from other fusion technologies, as their plasma exhibits densities 100,000 times higher and sustains fusion reactions for significantly longer durations.
In the race towards fusion energy development, each distinct approach necessitates specialized methodologies to determine net energy gain, which is denoted by the variable Q. This new publication, featured in the journal Fusion Science and Technology on June 5, elucidates Zap Energy’s approach to quantifying Q in their sheared-flow-stabilized Z-pinch fusion plasmas. This contribution is crucial for Zap Energy to demonstrate energy gain and progress towards constructing a commercial fusion system.
Uri Shumlak, Zap Energy’s co-founder, Chief Science Officer, and the lead author of the paper, states, “Our devices generate fusion-grade plasmas in a manner distinct from other fusion technologies. This publication lays the foundation for quantifying our progress.”
The Triple Product: Key to Fusion
In fusion, the triple product encompasses three essential variables: temperature, density, and time. These factors collectively determine the feasibility of achieving net energy gains in fusion. While different fusion concepts exist, all of them must scale up the triple product to attain significant energy gains. Credit: Zap Energy
Zap Energy’s approach shares similarities with other fusion devices, aiming to fuse hydrogen nuclei within plasma, a superheated material hotter than the sun. The properties of the plasma, including its temperature, density, and duration, contribute to the determination of Q, or net energy gain.
The triple product serves as a useful metric for comparing different fusion concepts. It enables a comparison between sheared-flow-stabilized Z-pinch devices, such as Zap Energy’s, and more traditional fusion devices like the tokamak, as well as other fusion approaches. Furthermore, the triple product can be used as a simplified measure for estimating Q.
Zap Energy generates fusion within a plasma filament that is less than two feet long. The inset image showcases a high-speed camera photo of a plasma in Zap’s device. Credit: Zap Energy
Zap Energy’s Z-pinch plasmas exhibit distinct characteristics, with densities approximately 100,000 times greater than those found in tokamaks and sustained durations lasting many microseconds. The company is currently developing a pulsed system that can repeatedly create such plasmas.
The flow of Zap’s plasmas follows a specific pattern, with different regions of the plasma moving at various speeds from the innermost part towards the outer edges. This mechanism, known as sheared-flow stabilization, enables the plasma to remain confined for a sufficient duration to sustain fusion reactions. While this approach eliminates the need for external magnets to confine the plasma, it necessitates unique measurement techniques and analysis.
Measuring Q
To calculate the triple product, Zap Energy measures the plasma’s temperature, density, and flow velocity to determine the duration of plasma confinement. The corresponding calculation of Q involves comparing the fusion power (output) to the input power, closely resembling the method used in other magnetic confinement approaches like the tokamak. In contrast, inertial confinement approaches, such as last year’s demonstration of Q>1 by Lawrence Livermore National Laboratory’s National Ignition Facility, focus on the ratio of fusion energy to input energy for defining Q due to their short-lived plasmas.
Zap Energy is making significant strides in enhancing fusion plasma performance within its FuZE-Q device. Credit: Zap Energy
The main distinction between power and energy lies in the fact that power refers to energy per unit of time. Since Zap Energy’s plasmas are confined for durations that fall between those of traditional magnetic confinement and inertial fusion approaches, choosing to calculate Q based on power is an important distinction.
“Publishing these technical details is of utmost importance. We cannot simply insert a thermometer into a fusion plasma to observe its behavior. Therefore, we rely on a combination of direct and indirect observations to gain insights into the plasma conditions,” explains Ben Levitt, Zap Energy’s Vice President of R&D. “This paper ensures that our methodology aligns well with established practices within the fusion community and outlines how we plan to report our results in the near future.”
Unique Aspects of Z-Pinch
The published paper delves into various details specific to Zap Energy’s fusion approach. One crucial aspect involves accounting for the input power required to drive the stabilizing plasma flow.
The paper also highlights that high-performance Z-pinches are likely to trap alpha particles, energetic byproducts of fusion reactions, which can enhance fusion gain by offsetting some of the necessary input power.
Zap Energy intends to correlate observations of plasma conditions with measurements of emitted neutrons. Neutrons serve as primary products of fusion reactions, so scientists anticipate their increase when fusion conditions are optimal and their decrease when they are not.
Zap Energy achieved its first plasmas in its fourth-generation device, FuZE-Q, in May of last year. Research and development campaigns are currently underway using FuZE-Q, and the Zap team will analyze results from both FuZE-Q and its predecessor, FuZE, in their pursuit of demonstrating sheared-flow-stabilized Z-pinch plasmas capable of achieving Q>1.
Reference: “Fusion Gain and Triple Product for the Sheared-Flow-Stabilized Z Pinch,” published on June 5, 2023, in Fusion Science and Technology. DOI: 10.1080/15361055.2023.2198049
Zap Energy is actively constructing a low-cost, compact, and scalable fusion energy platform that can confine and compress plasma without the need for expensive and complex magnetic coils. Zap’s sheared-flow-stabilized Z-pinch technology offers compelling fusion economics and requires significantly less capital compared to conventional approaches. With over one hundred team members across two facilities near Seattle, Zap Energy has garnered support from prominent financial and strategic investors.
Table of Contents
Frequently Asked Questions (FAQs) about fusion energy gain
What is Zap Energy’s innovative method for measuring fusion energy gain?
Zap Energy has developed a unique methodology to measure fusion energy gain, known as Q, in sheared-flow-stabilized Z-pinch fusion plasmas. They calculate the net energy gain by considering factors such as temperature, density, and duration of plasma confinement. This method allows them to quantify progress in fusion energy development.
How does Zap Energy’s approach differ from other fusion technologies?
Zap Energy’s sheared-flow-stabilized Z-pinch fusion plasmas exhibit significantly higher densities and longer durations compared to other fusion technologies like the tokamak. This distinct approach enables sustained fusion reactions without the need for external magnets. As a result, Zap Energy’s measurements and analysis techniques are tailored to suit these unique plasma properties.
What is the triple product in fusion, and why is it important?
The triple product in fusion refers to the combination of temperature, density, and time, which determines the feasibility of achieving net energy gains. It is a crucial factor in all fusion concepts. By scaling up the triple product, fusion technologies can aim for higher net energy gains. Comparing the triple product allows for assessment and comparison of different fusion approaches.
How does Zap Energy calculate Q, the net energy gain?
Zap Energy calculates Q by comparing the fusion power (output) to the input power. They measure the plasma’s temperature, density, and flow velocity to determine the duration of plasma confinement. This calculation aligns closely with the method used in other magnetic confinement approaches, such as the tokamak. By focusing on power rather than energy, Zap Energy’s calculations reflect the unique characteristics of their plasmas.
What are the implications of Zap Energy’s findings?
Zap Energy’s innovative methodology for measuring fusion energy gain is a significant step towards achieving sustainable fusion power. Their research contributes to the ongoing development of fusion technology and provides valuable insights into the progress of fusion energy systems. These findings have the potential to revolutionize the energy landscape by offering a low-cost, compact, and scalable fusion energy platform.
More about fusion energy gain
- Fusion Science and Technology: Link
- Lawrence Livermore National Laboratory’s National Ignition Facility: Link
- Zap Energy: Link
- Triple Product in Fusion: Link
- Tokamak: Link
- Fusion Community: Link
