Development of Nuclear Fusion Device using Electromagnetically confined Ions accelerating electrostatically

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A small LaB6 disk supported with a tantalum holder is inserted into tokarnak discharge plasmas with the discharge current of Ip=0.3~1.5 kA. It is supposed as an electron emitting cathode in which the electrode current of 100 A is easily obtained by arcing. The cross-field plasma resistance of tokamak magnetic configuration, Rr, has a scaling of Rr ∞ Bt^<1.0>Ig^<-(1.0~1.2)> for Ip = 0.5~1.5 kA where Bt is the toroidal magnetic field intensity and Ig is the electrode biasing current. The deepest potential well remains as deep as -0.3 kV.In the case of Ip less than 0.5 kA, the parameter dependency of potential well depth is quite changed compared with the previous case. When Bt 【greater than or equal】0.11 T, Rr becomes as large as 5 Ω and increases as Ip decreases, like Rr ∞ Ip^<(0.4~0.5)> For the following parameters : Ig【similar or equal】100A, Bt=0.13T and Ip=0.3kA, we obtain the deep potential well with -0.7 kV..One of the candidating physical mechanisms behind such a bifurcation like phenomena would be a generation of shock wave for Er×Bt poloidal plasma rotation to overcome the poloidal Alfven velocity. In the experiments a large potential oscillation has been observed, providing an interesting physical subject to be solved.Above these scalings and observations, we will obtain a deep potential well with a few kV in deuterium tokamak discharge by using the current pulsed voltage source (Maximum voltage : -5 kV ; Maximum current : 200 A ; Maximum pulse length : 250 micro-sec), which will make a basis for a new neutron source.