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Title: A Method of Tuning Resonant Loops

 [1];  [1];  [2]
  1. ORNL
  2. General Atomics
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: 17th Topical Conference on Radio Frequency Power In Plasmas, Clearwater, FL, USA, 20070507, 20070609
Country of Publication:
United States
Radio Frequency; DIII-D

Citation Formats

Baity Jr, F Wallace, Goulding, Richard Howell, and Pinsker, R. A Method of Tuning Resonant Loops. United States: N. p., 2007. Web.
Baity Jr, F Wallace, Goulding, Richard Howell, & Pinsker, R. A Method of Tuning Resonant Loops. United States.
Baity Jr, F Wallace, Goulding, Richard Howell, and Pinsker, R. Mon . "A Method of Tuning Resonant Loops". United States. doi:.
title = {A Method of Tuning Resonant Loops},
author = {Baity Jr, F Wallace and Goulding, Richard Howell and Pinsker, R.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}

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  • A convenient method of tuning resonant loops has been developed for use on the Long-Pulse Fast Wave Current Drive antennas on DIII-D. These 4-element antennas are fed from a single RF source, with a 90 deg. hybrid junction feeding two resonant loops. Each resonant loop connects a pair of non-adjacent current straps, and a decoupler allows independent impedance matching of each output leg of the hybrid junction. The tuning method involves only measurement of the reflection coefficient of each resonant loop and the transmission from one loop to the other. It will be shown that this method of tuning equalizesmore » the currents in all four current straps and 90 deg. phasing between adjacent elements.« less
  • White-beam synchrotron X-ray topography has been used to study the circular, prismatic, [0001] dislocation loops which are commonly-observed on the (0001) plane in polycrystalline, freshwater ice. A new method, involving detailed analyses of the effects of beam divergence on the loop images, has been developed to determine whether a loop is of vacancy of interstitial type. In an 0002 image, one half of a loop (projected as an ellipse) appears as a single image and the other half as a double image. Experimentally, it was found that the 0002 vector drawn from the center of a loop passes through themore » single image if the loop is of vacancy-type and through the double image if a loop is of interstitial-type. This method of loop characterization was confirmed by performing theoretical analyses of both the dislocation image widths and their strain fields.« less
  • This paper proposes a new tuning method when using a two degrees of freedom proportional-integral-derivative (PID) controller. Its control performance for a first-order lag plus deadtime system is shown as an example of the commonly approximated controlled plants in the heating, ventilating, and air-conditioning (HVAC) field. Reference and disturbance input changes to a conventional PID controller do not necessarily give a satisfactory response. To overcome this problem, several two degrees of freedom PID (2 DOF PID) algorithms have been developed to replace the conventional PID controllers. However, when these techniques are applied to real plants, it is not usually easymore » to obtain a set of optimum tuning parameters. To evaluate the control performance, a comparison is carried out between the two tuning methods--the optimization technique and the partial model matching method--using simulation. Graphs by which the controller parameters can be related to dynamics of a popular plant are developed. The 2 DOF PID control is studied taking into account modeling error due to a change in plant characteristics. It is found that the 2 DOF PID controller designed based on the partial model matching method is robust and useful in simulations where a traditional PID controller would be used.« less
  • The PEP II lattices are unique in their detector solenoid field compensation scheme by utilizing a set of skew quadrupoles in the IR region and the adjacent arcs left and right of the IP. Additionally, the design orbit through this region is nonzero. This combined with the strong local coupling wave makes it very difficult to calculate IP tuning knobs which are orthogonal and closed. The usual approach results either in non-closure, not being orthogonal or the change in magnet strength being too big. To find a solution, the set of tuning quads had to be extended which resulted havingmore » more degrees of freedom than constraints. To find the optimal set of quadrupoles which creates a linear, orthogonal and closed knob and simultaneously minimizing the changes in magnet strength, the method using Singular Value Decomposition, Response Matrices and an Adapted Moore Penrose method had to be extended. The results of these simulations are discussed below and the results of first implementation in the machine are shown.« less
  • A vibration technique has been developed to continuously maintain mode resonance and impedance match between a constant frequency magnetron Source and resonant cavity. This method uses a vibrating metal rod to modulate the volume of the cavity in a manner equivalent to modulating an adjustable plunger. A similar vibrating metal rod attached to a stub tuner modulates the waveguide volume between the source and cavity. A phase sensitive detection scheme determines the optimum position of the adjustable plunger and stub tuner during processing. The improved power transfer during the heating of a 99.8% pure alumina rod was demonstrated using thismore » new technique. Temperature-time and reflected power-time heating curves are presented for the cases of no tracking, impedance tracker only, mode tracker only and simultaneous impedance and mode tracking. Controlled internal melting of an alumina rod near 2000{degrees}C using both tracking units was also demonstrated.« less