Kumar Rajnish

Status of the ITER ion cyclotron heating and current drive system

The paper reports on latest developments for the ITER Ion Cyclotron Heating and Current Drive system: imminent acceptance tests of a prototype power supply at full power; successful factory acceptance of candidate RF amplifier tubes which will be tested on dedicated facilities; further design integration and experimental validation of transmission line components under 6MW hour-long pulses. The antenna Faraday shield thermal design has been validated above requirements by cyclic high heat flux tests. R&D on ceramic brazing is under way for the RF vacuum windows. The antenna port plug RF design is stable but major evolution of the mechanical design is in preparation to achieve compliance with the load specification, warrant manufacturability and incorporate late interface change requests. The antenna power coupling capability predictions have been strengthened by showing that, if the plasma scrape-off layer turns out to be steep and the edge density low, the reference burning plasma can realistically be di...

Design analysis of test bed with variable VSWR and variable phase angle for frequency range of 35 to 65 MHz

The ion cyclotron resonance frequency (ICRF) system is one of the most important ITER heating and current drive systems. Total 20 MW of RF power is required to be dumped on the ITER plasma using 8 nos. of RF sources, each capable of delivering 2.5 MW at VSWR 2 in the frequency range 35 - 65 MHz. RF power to the antenna should remain constant to its required value, even if source experiences VSWR of 2 at any phase angle. To qualify the RF sources without antenna, a test bed is to be fabricated to simulate antenna condition for the entire frequency band. The design analysis for the test bed has been done using RFSim99 software which consists of two phase shifters, one stub tuner and one matched 50 ohm dummy load. This paper describes the technical aspect of the design of this test bed.

Design and Development of Amplitude and phase measurement of RF signal with Digital I-Q Demodulator

ITER-India, working as a nodal agency from India for ITER project [1], is responsible to deliver one of the packages, called Ion Cyclotron Heating & Current Drive (ICH&CD) - Radio Frequency Power Sources (RFPS). RFPS is having two cascaded amplifier chains (10 kW, 130 kW & 1.5 MW) combined to get 2.5 MW RF power output. Directional couplers are inserted at the output of each stage to extract forward power and reflected power as samples for measurement of amplitude and phase. Using passive mixer, forward power and reflected power are down converted to 1MHz Intermediate frequency (IF). This IF signal is used as an input to the Digital IQ Demodulator (DIQDM). DIQDM is realized using National Instruments make PXI hardware & LabVIEW software tool. In this paper, Amplitude and Phase measurement of RF signal with DIQDM technique is described. Also test results with dummy signals and signal generated from low power RF systems is discussed here.

Real Time controller for R&D on ITER Ion Cyclotron Heating & Current Drive Source

IndianDomestic Agency is responsible for the development and delivery of total nine numbers of RF sources for ITER ion cyclotron heating and current drive (ICH and CD) system. To validate the design of RF amplifier source, a research and development program has been initiated. Each ICH and CD source consists of two chains of amplifier, and each chain composed of low-power RF section, one solid-state power amplifier followed by two cascaded tunable high-power tube (tetrode/diacrode)-based amplifiers, high-voltage/high-current power supplies, and control system. A dedicated data acquisition and control system has been developed based on real-time (RT) PXI controller. To demonstrate the performance of RF source as required by ITER, two RT control for anode voltage regulation and voltage standing wave ratio (VSWR) for maintaining constant load power is implemented on field-programmable gate array (FPGA) module. To protect high-power RF tubes and related subsystems, interlock logic is implemented on another FPGA module, which will suppress RF input drive and switch off different biasing power supplies within

Status of R&D activity for ITER ICRF power source system

10~\mu \text{s}

Real-Time Controller for Research and Development on ITER Ion Cyclotron Heating and Current Drive Source

. To operate RF amplifier as per experimental requirement, user settable parameters (

Initial operation of 3 MW dual output high voltage power supply with IC RF system

T_{\mathrm{\scriptscriptstyle ON}}- T_{\mathrm{\scriptscriptstyle OFF}}

Integration & Validation of LCU with Different Sub-systems for Diacrode based amplifier

time, number of pulses, allowed number of faults before terminating the pulse, and rise time and fall time) for RF pulse generation are incorporated into application software developed using LabVIEW platform. Two modes of data acquisition function are implemented using NI PXI-8108 RT controller (embedded real time operating system controller). All analog and digital signals for status and health monitoring of different subsystems, normal acquisition mode having 1-ms sampling rate, are implemented. For fault analysis purpose, data are acquired with 1-

Status of the ITER Ion Cyclotron H&CD

\mu \text{s}

Design, development and testing of real time control and data acquisition system for R&D IC H&CD source

sampling frequency in trigger mode of acquisition with 100-ms predata and 100-ms postdata considering fault event as trigger for the acquisition. In this paper, architecture of RT controller is discussed in detail and various operational results are presented.