Radially inward turbulent particle flux is observed in the core region of target plasma of Large Volume Plasma Device(LVPD)where electron temperature driven turbulence condition satisfied region satisfy conditions for ETG turbulence, i.e. threshold condition, η e = L ne /L Te > 2/3 , where density scale length, L ne ∼ 300cm and temerature scale length, L Te ∼ 50cm[S.K. Mattoo et al., Phys. Rev. Lett., 108, 255007(2012) 1 ]. The measured flux is dominantly electrostatic (Γ es ≈ 10 5 Γ em ) although the nature of the measured turbulence is electromagnetic(β ≈ 0.6). The turbulence has been established as a consequence of electron temperature gradient (ETG) driven modes. Experimental observations of phase angle between density (n e ) and potential (φ) fluctuations, θñ e ,φ and electrostatic particle flux, Γ es shows good agreement with the corresponding theoretical estimates for ETG turbulence.

RF systems in the ion cyclotron resonance frequency (ICRF) range and electron cyclotron resonance frequency (ECRF) range are in an advanced stage of commissioning, to carry out pre-ionization, breakdown, heating and current drive experiments on the steady-state superconducting tokamak SST-1. Initially the 1.5 MW continuous wave ICRF system would be used to heat the SST-1 plasma to 1.0 keV during a pulse length of 1000 s. For different heating scenarios at 1.5 and 3.0 T, a wide band of operating frequencies (20–92 MHz) is required. To meet this requirement two CW 1.5 MW rf generators are being developed in-house. A pressurized as well as vacuum transmission line and launcher for the SST-1–ICRF system has been commissioned and tested successfully. A gyrotron for the 82.6 GHz ECRF system has been tested for a 200 kW/1000 s operation on a water dummy load with 17% duty cycle. High power tests of the transmission line have been carried out and the burn pattern at the exit of transmission line shows a gaussian nature. Launchers used to focus and steer the microwave beam in plasma volume are characterized by a low power microwave source and tested for UHV compatibility. Long pulse operation has been made feasible by actively cooling both the systems. In this paper detailed test results and the present status of both the systems are reported.

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