交变磁场作用下高温超导体温度变化研究

高温超导体在交变的磁场作用下,由于磁通的运动引起能量损耗,损耗的能量一部分通过超导体表面传递到冷却剂中,另一部分将使得超导体的温度升高。文中用数值的方法研究了外加磁场速度在0.0005T/s—5T/s变化情况下超导体的温度变化;当外磁场的速度由小到大变化时,超导板的状态会发生从稳定→不稳定(磁通跳跃)→稳定的变化;慢变磁场作用下超导体的温度在接近冷却剂温度的温区作微幅的周期性变化,当外加磁场速度比较大时,超导体发生磁通跳跃,温度也呈跳跃性变化,进一步加大外磁场速度,磁通和温度呈准周期的振荡型变化,而且振荡幅值随外磁场速度的增加逐渐减小,最后振荡消失,超导体在更高的温区稳定运行,温度呈周期性变化。

Temperature change of high temperature superconductor subjected to alternating magnetic field

The high temperature superconductors subjected to alternating magnetic field,due to flux diffusion,product energy loss,part of energy dissipation transmits to cooler while other part of it enhance superconductor temperature.In the present paper numerical method employed investigates temperature change in the high TC superconductor as applied magnetic field sweep rate increase from 0.0005T/s to 5T/s.Results show that superconductor make change from stability to instability again to stability along with magnetic field sweep rate increase.Temperature of superconductor subjected to slowly varying magnetic field make periodic change of small amplitude over cooler temperature.Flux and temperature jump take place with sweep rate more increase,and with further increase of sweep rate flux and temperature produce quasi-periodic oscillation.Finally,oscillation of flux and temperature disappear for larger sweep rate,and again superconductor reach stability in the higher temperature range that makes periodic change.