Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

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.

Measurement of charged-particle stopping in warm dense plasma

We measured the stopping of energetic protons in an isochorically heated solid-density Be plasma with an electron temperature of ∼32  eV, corresponding to moderately coupled [(e^{2}/a)/(k_{B}T_{e}+E_{F})∼0.3] and moderately degenerate [k_{B}T_{e}/E_{F}∼2] "warm-dense matter" (WDM) conditions. We present the first high-accuracy measurements of charged-particle energy loss through dense plasma, which shows an increased loss relative to cold matter, consistent with a reduced mean ionization potential. The data agree with stopping models based on an ad hoc treatment of free and bound electrons, as well as the average-atom local-density approximation; this work is the first test of these theories in WDM plasma.

Crossing boundaries: communication between professional groups

The NHS reforms increased emphasis on a managerial culture. In primary care this raised questions about responsibility and philosophical approaches. Greater integration between agencies brings benefits, but creates tensions. Failure to bridge the gap may result in dysfunctional teams and compromised quality of patient care. The different orientations may manifest themselves in several ways but lead to frictions that can breed hostility and prevent effective teamwork. Explores issues involving social service and community nurse teams in Dorset to identify a new framework for working, by recognizing and respecting differences and by creating a climate of dialogue. The process involves three stages. First, mutual awareness by use of meta planning which revealed several important themes, different priorities, political dynamics and organizational constraints. Second, behavioural contracting facilitated by role reversal and third, the development of consensus working protocols as a bridge for professional gaps.

Medicine and management: a conflict facing general practice?

Partners and practice managers are beginning to understand implications of management issues raised by recent reforms. Practices involved in this study agree the need for improvement, but partners and managers were often unable to define improvements needed. Demonstrates that effective management structure is vital to future success for general practice. To achieve this involves understanding new managerial challenges practices must meet and different organizational competences required. To change requires a radical restructure of many practice roles and several options are considered. Regardless of the chosen option the question of training remains. There is a need to involve consultants, managers, and doctors already advancing the boundaries of practice development, in a dialogue with institutions providing management training, to design suitable programmes. Academic institutions too often produce management programmes geared towards the old environment, whereas managerial skills which changes in the NHS demand from future practice managers are now required.

Aspects of psychology in sports medicine

Psychology's impact as an ergogenic aid across sports and competitive levels has been well documented. In addition, exercise can play a major role in disease prevention and health enhancement while also enhancing psychological well-being. In addition to its preventive value, exercise is being recognized as a valuable therapeutic tool. Like most therapeutic modalities, however, exercise also has some potentially negative qualities.