In order to acquire a broadband absorption spectrum in a single shot, a compact radiation source was developed by using a Z-pinch type electric discharge. This paper presents the mechanical and electrical construction of the source, as well as its electrical and optical characteristics, including the intense continuum of radiation emitted by the source in the UV and visible spectral range. It also shows that the compactness of the source allows direct coupling with the probed medium, enabling broadband absorption measurement in the spectral range of 200e300 nm without use of an optical fiber which strongly attenuates the light in the short wavelength range. Concretely, thanks to this source, broadband spectral absorption of NO molecules around 210 nm and that of OH molecules around 310 nm were recorded in this direct coupling arrangement. Copper atom spectral absorption around 325 nm of the peripheral cold zones of an intense transient arc was also recorded. Copyright ? 2016 Science and Technology Information Center, China Academy of Engineering Physics. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Dense Z-pinch plasmas are powerful and energy-efficient laboratory sources of X-rays, and show the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch and Z-pinch dynamic hohlraum (ZPDH) researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. Models are setup to study different physical processes. A full circuit model (FCM) was used to study the coupling between Z-pinch implosion and generator discharge. A mass injection model with azimuthal modulation was setup to simulate the wire-array plasma initiation, and the two-dimensional MHD code MARED was developed to investigate the Z-pinch implosion, MRT instability, stagnation and radiation. Implosions of nested and quasi-spherical wire arrays were also investigated theoretically and numerically. Key processes of ZPDH, such as the arrayefoam interaction, formation of the hohlraum radiation, as well as the following capsule ablation and implosion, were analyzed with different radiation magneto-hydrodynamics (RMHD) codes. An integrated 2D RMHD simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire-array plasma acceleration, shock generation and propagation, hohlraum formation, radiation ablation, and fuel compression.

The spherical torus (ST) and compact torus (CT) are two kinds of alternative magnetic confinement fusion concepts with compact geometry. The ST is actually a sub-category of tokamak with a low aspect ratio; while the CT is a toroidal magnetic configuration with a simply-connected geometry including spheromak and field reversed pinch. The ST and CT have potential advantages for ultimate fusion reactor; while at present they can also provide unique fusion science and technology contributions for mainstream fusion research. However, some critical scientific and technology issues should be extensively investigated.

Research progresses on Cherenkov and transit-time high-power microwave (HPM) sources in National University of Defense Technology (NUDT) of China are presented. The research issues are focused on the following aspects. The pulse-shortening phenomenon in O-type Cerenkov HPM devices is suppressed. The compact coaxial relativistic backward-wave oscillators (RBWOs) at low bands are developed. The power efficiency in M-Type HPM tubes without guiding magnetic field increased. The power capacities and power efficiencies in the triaxial klystron amplifier (TKA) and relativistic transit-time oscillator (TTO) at higher frequencies increased. In experiments, some exciting results were obtained. The X-band source generated 2 GW microwave power with a pulse duration of 110 ns in 30 Hz repetition mode. Both L- and P-band compact RBWOs generated over 2 GW microwave power with a power efficiency of over 30%. There is approximately a 75% decline of the volume compared with that of conventional RBWO under the same power capacity conditions. A 1.755 GHz MILO produced 3.1 GW microwave power with power efficiency of 10.4%. A 9.37 GHz TKA produced the 240 MW microwave power with the gain of 34 dB. A 14.3 GHz TTO produced 1 GW microwave power with power efficiency of 20%.