Observation of 'H'-like phenomena at the beginning phase of ECR heating on T-10

Auxiliary heating is known to result in a significant increase of the neutral flux and Hα/Dα intensity, which is typical for 'L'-mode. It's not before the certain rise in temperature and exceeding some threshold power, that transition to 'H'-mode becomes possible. After that, the particle fluxes and Hα/Dα intensity fail to practically ohmic values. A high recycling value in the main plasma, causing high value of the neutral fluxes, is usually considered as one of the factors, which make difficult transition to 'H'-mode. In this case, as it may seem, the formation of 'H'-mode is possible at the beginning of the central ECR-heating, before the wave of perturbation due to heating reaches the wall and causes neutral flux increase. It has been shown in the present paper, that in this case 'H'-like phenomena did take place in first 10-13 ms of ECRH, namely, increases of ne and Te gradients at the plasma periphery under the condition of ohmic values of the neutral fluxes. (author) 3 refs., 5 figs