An Overview of the LM26 Program and Related Plasma Diagnostic Systems in General Fusion

Since 2009, General Fusion has made significant investments in the development of core technologies and is now embarking on the design and construction of a small-scale device employing a solid lithium liner and magnetic compression. This device, known as Lawson Machine 2026 (LM26), utilizes an advanced Marshall gun plasma injector developed through multiple generations of 38 cm-scale systems. These injectors have demonstrated the temperatures, densities, and confinement times necessary for scaling up to reactor-relevant conditions.



LM26 includes a large-scale injector capable of producing spherical tokamak plasmas with plasma currents of up to 0.5 MA. These plasmas are injected into a high-vacuum-compatible composite chamber, whose inner surface is covered with a 7 cm thick solid lithium liner that acts as the plasma-facing component. A surrounding array of magnetic coils generates a strong magnetic field to symmetrically compress the liner and the plasma it contains through near-adiabatic compression, aiming to reach the required high temperatures and densities. GF's capabilities in Marshall gun technology remain among the most advanced in the world.



LM26 will proceed in two main phases: a 1 keV compression phase and a 10 keV compression phase. The first phase aims to design and build a plasma compression system capable of increasing the plasma volume density by an order of magnitude and raising plasma temperature to 1 keV. To assess plasma properties and the evolution of compression dynamics, a comprehensive suite of diagnostics is employed. These include AXUV electron temperature diagnostics, a dual-color interferometer system, visible and UV ion Doppler spectroscopy, visible and VUV spectrometers, AXUV bolometry, neutron scintillators, high-speed imaging, liner diagnostic systems, and magnetic sensors.



This poster provides an overview of the LM26 machine and its diagnostics, which have been developed in-house at General Fusion or in collaboration with external plasma research groups. Also, a set of preliminary results from recent plasma compressions will be presented.