Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

No-till farming systems for sustainable agriculture: an overview

No-till (NT) farming systems have revolutionized agriculture by improving erosion control, soil water storage, soil quality and, in many instances, yield and net farm income. The adoption of NT systems has increased at an exponential rate since the 1990s and they are now used on 12.5% of global croplands. However, while the development of NT systems has seen much success, there can be significant agronomic, economic and/or social challenges associated with their use that limit large scale worldwide adoption. In addition, where NT is not implemented as part of an integrated system that incorporates stubble retention and appropriate crop rotations to help manage weeds, diseases, pests and soil fertility, decreases in yield can be observed. A combination of research, education and good policy development to remove economic/institutional and social barriers to uptake are required to ensure the continued success of NT. In particular, the tailoring of NT farming systems according to individual locations and the introduction of some flexibility in approach to tillage management can provide an opportunity to manage some of the challenges of NT farming systems