John D. Lawson passed away
John D.Lawson, well known for his derivation of the Lawson criterion, a fundamental criterion (or principle) in fusion research, originally trained as an engineer. Through a series of coincidences he became involved in fusion research from its early days, and made important contributions that continue to influence the design of proposed fusion reactors.
The Lawson criterion: The Lawson criterion states that the product of the particle density of a plasma in particles per cm3 and the containment time in seconds at or above its ignition temperature, such that fusion energy released equals the energy required to produce and confine the plasma. In other words, for a successful fusion reactor, the aim is to get more energy out than you have to put in. The criterion is a constant equivalent to the product of plasma density x confinement time. The aim in fusion reactor design is to satisfy the criterion.