铁心对线圈不同连接方式下电感的影响

以交流伏安法作为电感的测量手段,在保持线圈相对位置不变的前提下,对有无铁心的情况分别进行测量,对比研究了线圈不同连接方式下电感的变化规律,分析了铁心对电感的作用和影响。结果表明:采用不同的连接方式,总回路中的电感值不同,四个线圈反串的连接方式是最合适的;铁心对线圈的互感产生决定性影响,不同电流下的电感值不同。     

Recent Progress of the HL-2A Multi-Channel HCOOH Laser Interferometer/Polarimeter

A multichannel methanoic acid（HCOOH,λ= 432.5μm） laser interferometer/polarimeter is being developed from the previous eight-channel hydrogen cyanide（HCN,λ=337 μm） laser interferometer in the HL-2A tokamak.A conventional Michelson-type interometer is used for the electron density measurement,and a Dodel-Kunz-type polarimeter is used for the Faraday rotation effect measurement,respectively.Each HCOOH laser can produce a linearly polarized radiation at a power lever of ³0 mW,and a power stability <10%in 50 min.A beam waist（diameter d₀≈12.0 mm,about 200 mm away from the outlet） is finally determined through a chopping modulation technique.The latest optical layout of the interferometer/polarimeter has been finished,and the hardware data processing system based on the fast Fourier transform phasecomparator technique is being explored.In order to demonstrate the feasibility of the diagnostic scheme,two associated bench simulation experiments were carried out in the laboratory,in which the plasma was simulated by a piece of polytetrafluoroethene plate,and the Faraday rotation effect was simulated by a rotating half-wave plate.Simulation results agreed well with the initial experimental conditions.At present,the HCOOH laser interferometer/polarimeter system is being assembled on HL-2A,and is planned to be applied in the 2014-2015 experimental campaign.     

Research on the phase adjustment method for dispersion interferometer on HL-2A tokamak

A synchronous demodulation system is proposed and deployed for CO_2 dispersion interferometer on HL-2 A,which aims at high plasma density measurements and real-time feedback control.In order to make sure that the demodulator and the interferometer signal are synchronous in phase,a phase adjustment(PA) method has been developed for the demodulation system.The method takes advantages of the field programmable gate array parallel and pipeline process capabilities to carry out high performance and low latency PA.Some experimental results presented show that the PA method is crucial to the synchronous demodulation system and reliable to follow the fast change of the electron density.The system can measure the lineintegrated density with a high precision of 2.0?×?10~(18)m~(-2).