M. A. Ansari

APPEL device experimental studies on spiral antenna for efficient pre-ionization in SST-1 tokamak

Yashashri Patil, S. K. Karkari, M. A. Ansari, Varun Dixit et autres

Abstract Plasma initiation in mid-sized tokamaks, especially superconducting machines, requires a pre-ionization source having an electron density on the order of 1017–1018 m−3 that typically operates in the pressure range between 10−5 and 10−4 mbar. A spiral antenna excited by 13.56 MHz …

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Characterization of Plasma Discharge in a Multi Dipole Line Cusp Magnetic Field Created by an RF Source Coupled by a Spiral Antenna

M. A. Ansari, A. D. Patel, A. Das Alli, Prabal Kumar Chattopadhyay et autres

A detailed characterization of RF–plasma discharge in the multi-cusp plasma device (MPD) having a multi-dipole line cusp magnetic field (MMF:$B_{0}$) has been experimentally demonstrated using the externally employed four turns high power spiral antenna. The experimentally measured input impedance ($\sim $0.37 +$\text{j}80\,\Omega$) …

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Preliminary Experimental Studies of the Proposed High Power RF Antenna to assist Glow Discharge Cleaning of SST-1 at Low Pressure

M. A. Ansari, Uttam Kumar Goswami, Dharmendra Rathi, Yuvakiran Paravastu et autres

The wall conditioning system for Steady-state Superconducting tokamak (SST-1) with a high power RF antenna to assist the glow discharge cleaning (GDC) is developed to operate at the low pressure. The antenna is designed as per the SST-1 port space constraints and …

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Design and Construction of a Traveling Wave Electron Linear Accelerator at Institute for Research in Fundamental Sciences (IPM)

Mahyar Shirshekan, H. Shaker, Farshad Ghasemi, M. A. Ansari et autres

In this paper, the design and construction process of a traveling wave electron linear accelerator is presented briefly. The machine consists of an electron gun followed by a prebuncher, a traveling wave buncher, an accelerating tube and the diagnostics instruments. Solenoid magnets …

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Modeling of RF Pulse Shortening Causes and Their Effects on an Overmoded RBWO Under Low Guiding Magnetic Field

V. Venkata Reddy, M. A. Ansari, Muthiah Thottappan

The overmoded slow wave structure (OSWS) and trapezoidal resonant reflector (TRR) have been used to study their effects on the microwave generation time in relativistic backward wave oscillator (RBWO) at the lower guiding magnetic field using a finite difference time domain (FDTD) …

An Adaptive Multi Branch Dual Band Rectifier for RF Energy Harvesting Efficiency Improvement

M. A. Ansari, Salahuddin Raju

The RF energy harvester has promising application in making the IoT nodes self-sufficient in wireless sensor network. However, current state of the art lacks RF-DC conversion efficiency at lower incident power and output DC voltage level. In this paper, two multi-branch power …

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Simulation Investigations of High Power Overmoded Relativistic Backward Wave Oscillator with Trapezoidal Resonant Reflector

V. Venkata Reddy, M. A. Ansari, Muthiah Thottappan

An S-band high power relativistic backward wave oscillator using a trapezoidal resonant reflector and overmoded slow-wave structure is demonstrated by finite difference time domain based Particle-In-Cell code. The trapezoidal resonant reflector and slow-wave structure are chosen to improve the RBWO power handing …

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PIC Simulation Studies of High Power RBWO with Trapezoidal Resonant Reflector at Low Guiding Magnetic Field

V. Venkata Reddy, M. A. Ansari, Muthiah Thottappan

In this paper, an S-band Relativistic Backward Wave Oscillator (RBWO) with Trapezoidal Resonant Reflector (TRR) has been studied at low guiding magnetic field by using 3D Particle-In-cell (PIC) code. The overmoded TRR and slow-wave structure (SWS) are more favourable in view of …

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Design and Simulation of Dual-Band Nonuniform Relativistic Backward Wave Oscillator Using a Bragg Structure as Its RF Circuit and Reflector-Cum-Mode Converter

M. A. Ansari, Muthiah Thottappan

A relativistic backward wave oscillator (RBWO) operating in dual (C and X) band is designed and studied using finite-difference time domain (FDTD) particle-in-cell (PIC) simulations implemented in MAGIC. It consists of a sinusoidally corrugated, moderately overmoded nonuniform slow wave structure (SWS) in …

Studies of Pulse Shortening Phenomena and Their Effects on the Beam–Wave Interaction in an RBWO Operating at Low Magnetic Field

M. A. Ansari, Muthiah Thottappan

Particle-in-cell (PIC) simulations using the MAGIC-3D code are performed to illustrate the beam-wave interaction behavior and the effects of pulse shortening in relativistic backward wave oscillator (RBWO) operating at a low guiding magnetic field. The causes of pulse-shortening phenomena such as beam …

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Microdosimetric modeling of the sensitometric curve of GafChromic films in the photon fields

Amir Hossein Moslehi, M. A. Ansari, Sh. Monadi

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Simulation Studies of an Overmoded RBWO under Low Guiding Magnetic Field

V. Venkata Reddy, M. A. Ansari, Muthiah Thottappan

An overmoded sinusoidally corrugated Relativistic Backward Wave Oscillator (RBWO) has been designed and simulated for Gigawatt power level at low guiding magnetic field. In the upstream, a trapezoidal cavity resonant reflector (TRR) is used to reduce the over modulation of the electron …

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