Aparajita Mukherjee

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...

Development of traveling wave resonator based test bed for high power transmission line component testing

India is responsible for delivery of 8+1(prototype) RF sources to ITER Organization. Each RF source will provide 2.5MW of RF power at 2 VSWR in the frequency range of 35 to 65MHz. Eight such RF sources will generate total 20MW of RF power. A large number of high power transmission line components are required for connecting various stages of RF source. To test these passive transmission line components at high power, prior to connecting with RF source system, a test facility is required. India is developing a 3MW test facility based on the concept of Traveling Wave Resonator (TWR) for testing of transmission line components. TWR is basically a ring resonator which will build high power under certain operation condition at resonant frequency (∼55MHz in this case). In TWR, power is fed to the ring via a directional coupler continuously which leads to development of high circulating power in the ring. The voltage and current magnitude inside the ring increases with the increasing circulating power. Detailed ...

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.

Wilkinson Type Lumped Element Combiner-Splitter for Indigenous Amplifier Development

Development of wideband solid state power amplifier in ITER [1] ICH&CD frequency range is ongoing. A 12 kW/CW Solid State Power Amplifire (SSPA) is being developed in house. 1 × 16 wideband splitter/combiner will be used at input/output side. Study has been carried out on two options i.e. coaxial type & lumped element based Wilkinson splitter/combiner. Tentative power level of both input N-Type ports of combiner is ~ 1 kW. Design and simulation for coaxial type Wilkinson combiner is done. Quarter wave length for centre frequency is ~ 1500 mm. To reduce mechanical dimension of combiner, PTFE dielectric is used with sophisticated arrangement. Coaxial combiner required unique fabrication process. Alternate option is proposed as a lumped element based Wilkinson combiner with reduced size, cost & development time. Design and simulation was carried out. Required PCB design & fabrication was done accordingly. Same design will be implemented for splitter as well. Design scheme for the splitter/combiner will be finalized depending on the achieved performance of both the designs. In this paper, detailed design, simulation and test results are presented for both types of combiners. A detailed comparison of combiners is provided.

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

Development of MisMatch Transmission Line (MMTL) system for ICH&CD test rig

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Landslide hazard susceptibility mapping based on terrain and climatic factors for tropical monsoon regions

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

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

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

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-

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

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