Magneto-Inertial Fusion

Abstract

In this community white paper, we describe an approach to achieving fusion which employs a hybrid of elements from the traditional magnetic and inertial fusion concepts, called magneto-inertial fusion (MIF). The status of MIF research in North America at multiple institutions is summarized including recent progress, research opportunities, and future plans.Keywords Magneto-inertial fusion Á Magnetized target fusion Á Liner Á Plasma jets Á Fusion energy Á MagLIF DescriptionMagneto-inertial fusion (MIF) (aka magnetized target fusion) [1][2][3] is an approach to fusion that combines the compressional heating of inertial confinement fusion (ICF) with the magnetically reduced thermal transport and magnetically enhanced alpha heating of magnetic confinement fusion (MCF). From an MCF perspective, the higher density, shorter confinement times, and compressional heating as the dominant heating mechanism reduce the impact of instabilities. From an ICF perspective, the primary benefits are potentially orders of magnitude reduction in the difficult to achieve qr parameter (areal density), and potentially significant reduction in velocity requirements and hydrodynamic instabilities for compression drivers. In fact, ignition becomes theoretically possible from qr B 0.01 g/cm 2 up to conventional ICF values of qr * 1.0 g/cm 2 , and as in MCF, Br rather than qr becomes the key figure-of-merit for ignition because of the enhanced alpha deposition [4]. Within the lower-qr parameter space, MIF exploits lower required implosion velocities (2-100 km/s, compared to the ICF minimum of 350-400 km/s) allowing the use of much more efficient (g C 0.3) pulsed power drivers, while at the highest (i.e., ICF) end of the qr range, both higher gain G at a given implosion velocity as well as lower implosion velocity and reduced hydrodynamic instabilities are theoretically possible. To avoid confusion, it must be emphasized that the wellknown conventional ICF burn fraction formula does not apply for the lower-qr ''liner-driven'' MIF schemes, since it is the much larger mass and qr of the liner (and not that of the burning fuel) that determines the ''dwell time'' and fuel burnup fraction. In all cases, MIF approaches seek to satisfy/ exceed the inertial fusion energy (IFE) figure-of-merit gG * 7-10 required in an economical plant with reasonable recirculating power fraction. A great advantage of MIF is indeed its extremely wide parameter space which allows it greater versatility in overcoming difficulties in implementation or technology, as evidenced by the four diverse approaches and associated implosion velocities shown in Fig. 1.MIF approaches occupy an attractive region in thermonuclear q-T parameter space, as shown in a paper by

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“…正是由于 MCF 与 ICF 的极端参数条件促使了科学家们探索等离子体 参数介于两者之间的聚变新途径. 一般来说, 对于同 时具有惯性约束聚变和磁约束聚变特征, 等离子体参 数介于两种传统聚变方法之间的新型聚变途径统称 为磁惯性约束聚变 [22] (Magneto-Inertial Confinement, MIF). [21] 认为这主要 和等离子体所需能量 (ITER) 以及等离子体加热速率 (NIF) 有关.…”