Complex Turbulence Regime At Skico-1 Device

As it has been emphasized in the previous studies /1/, in order to generate different types of compact toroids such as spheromak, spherical torus and spherical pinch tokamak in the hybrid SK/CG-1 machine a magnetically driven C-gun having a high helicity injection efficiency is used. In the SK/CG-1 machine, using the He gas pressures between 30 and 50 mTorr, a complex turbulence regime has been determined. To obtain the experimental data, besides the electrical surface, cylinderical Langmuir (similar to the charge exchange cell) and magnetic probes, the time and frequency domain analysis systems are also utilized. During the on-set phase of 0.3S u3, together with the anomalous plasma resistivity, the micro instabilities are also observed. At the C-gun, the plasma belt which contains the hot electrons at the energy range of 60-80 eV, breaking from the gun electrodes, the translation into plasmoid case occures and than high electric fields of about 5 kV/cm are produced in the poloidal frame of the gun. Thus the electron-ion two stream insability and just after it in 0.1 u3, the ion acoustic instability are started. On the other hand, in the second phase, the beam plasma and the ion acoustic instabilities are sustained parallelly. The beam plasma instability includes also the W3 ion cyclotron instability In addition, due to the toroidal magnetic field of the poloidal frame and the electric field perpendicular to it, the density and temperature gradients are come into existence. At the end of the resonance of drift and ion acoustic waves probably, the drift wave turbulence commences. The time constant of the octagonal flux conserver is about 28-30 ms.