Lawson criterion

Assembled from 11 blocks · 2 evidence · 7 related

1. Story
2. The Lawson criterion, formulated by John D. Lawson in 1955, states the minimum combination of plasma parameters at which the energy released by fusion reactions equals or exceeds the energy needed to keep the plasma hot against its own losses. Lawson's original form used density and confinement time; the triple product is the modern working version that folds in temperature. Generalised forms exist for inertial confinement, where the analogue is expressed through areal density and hot-spot conditions rather than a confinement time. It matters here as the reference standard for what counts as ignition: NIF's August 2021 shot was reported as exceeding the Lawson criterion for ignition, and the December 2022 shot as significantly exceeding it while also achieving target gain above one. Exceeding the Lawson criterion is a statement about the plasma, not about a facility's power balance.
3. Knowledge
4. Lawson criterion
5. Connections
6. Fusion triple product (n·T·τ_E)
7. NIF exceeds the Lawson criterion for ignition
8. NIF achieves target gain greater than unity for the first time
9. Evidence
10. The 8 August 2021 NIF shot produced about 1.35 MJ of fusion yield and exceeded the Lawson criterion for ignition without reaching target gain above unity
11. On 5 December 2022 a NIF indirect-drive implosion achieved a target gain of 1.5, with 2.05 MJ of 351 nm laser light producing about 3.1 MJ of fusion yield and significantly exceeding the Lawson criterion for ignition