Alpha Particles Slow Burning Dt Plasma Fusion

In inertial confinement fusion(ICF),the energy deposition of charged particle plays an important role in fusion ignition and thermonuclear burn.The purpose of this paper is to study the slowing down effect in thermonuclear burn of alpha particle produced by D-T fusion reaction.Some concepts of ICF and the importance of charged particle energy deposition are introduced in chapter 1.A survey of the approaches used in describing the slowing down of charged particles is also presented and the development of thermonuclear burn models is also reviewed in chapter 1.In chapter 2,the energy loss rate and stopping power of an alpha particle moving in D-T plasma are derived within the binary collision(BC)treatments which considered the stopping is caused by the energy transfers in successive binary collisions between alpha particle and the particles in plasma,including ions and electrons.The spatial and temporal distribution of the energy deposited by an alpha particle in fully ionized D-T plasma is calculated.The manner in which an alpha particle distributes its energy in plasma is investigated.In chapter 3 and 4,a two-temperature thermonuclear burn model considering alpha-particle slowing-down process is then presented.Compared with the model which considering alpha particle depositing its energy instantaneously into the plasma, the temporal evolution of plasma temperature and particle number density are calculated.The slowing down effect of alpha particles during thermonuclear burn has been studied.Having investigated the manner in which the thermonuclear fuel burns. The alpha particle source terms to electrons and ions are presented,in which the slowing down of alpha particle have been considered.Based on the source terms and fusion burn-up equations,a three-temperature plasma model is founded in which the electrons,ions,and the radiation filed are represented by separate temperatureskT_e,kT_i and kT_r,respectively,where kT_r is characterized by a Planckian distribution.Using this three-temperature model,the description of the alpha particles slowing down during thermonuclear burn is more detailed.Calculation shows that the slowing-down of alpha particles delay ignition time,make electron and ion temperature peak lower and is more remarkable for lower density conditions. Chapter 5 gives a summary of this work and proposes some advises to improve the two- and three-temperature model in the future.