Journal ArticleDOI
Broadband superheterodyne tracking circuits for millimeter‐wave measurements
TLDR
A feedforward tracking technique is described and its application to single frequency millimeter-wave interferometry and Doppler-shift scattering measurements on tokamak plasmas is described.Abstract:
Superheterodyne stimulus‐response measurements can be made with high dynamic range, but are often sensitive to oscillator frequency drift and noise. The usual techniques for reducing this sensitivity often become impractical at millimeter‐wave frequencies and above. This paper describes a feedforward tracking technique and its application to single frequency millimeter‐wave interferometry and Doppler‐shift scattering measurements on tokamak plasmas. Swept frequency transmission measurements can also be made with high dynamic range using this technique.read more
Citations
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Journal ArticleDOI
THz Imaging Radar for Standoff Personnel Screening
Ken B. Cooper,Robert J. Dengler,Nuria Llombart,Bertrand Thomas,Goutam Chattopadhyay,Peter H. Siegel +5 more
TL;DR: A summary of the NASA Jet Propulsion Laboratory's 675 GHz imaging radar is presented, with an emphasis on several key design aspects that enable fast, reliable through-clothes imaging of person-borne concealed objects.
Journal ArticleDOI
Heterodyne methods in millimetre wave plasma diagnostics with applications to ECE, interferometry and reflectometry
TL;DR: In this paper, the basic principles of heterodyne techniques are introduced and various components of a heterogeneous system are summarized, and the diagnostic applications in ECE, interferometry and reflectometry are discussed after introducing the diagnostic principles.
Journal ArticleDOI
Microwave reflectometry for magnetically confined plasmas
TL;DR: In this paper, the role of short-scale density fluctuations is discussed at length, both as a unique diagnostic tool for turbulence studies in thermonuclear plasmas and for the deleterious effects that fluctuations may have on the measurement of the average plasma density with microwave reflectometry.
Journal ArticleDOI
Diagnostic instrumentation for microturbulence in tokamaks
TL;DR: In this paper, a review of the primary instruments that have been developed to measure fluctuating quantities associated with transport: density, n, temperature, δT, potential and magnetic field, and their correlations.
Journal ArticleDOI
Chapter 3: Microwave Diagnostics
Neville C. Luhmann,Henrik Bindslev,Hyeon K. Park,Jesús A. Vega Sánchez,G. Taylor,Changxuan Yu +5 more
TL;DR: Microwave-based diagnostics have found broad application in magnetic fusion plasma diagnostics and are expected to be widely employed in future burning plasma experiments (BPXs) as mentioned in this paper.
References
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Journal ArticleDOI
Plasma diagnostics with microwaves
Journal ArticleDOI
Low‐frequency microinstabilities in the PLT tokamak
TL;DR: In this article, a turbulence with wavelengths in the range 2-0.2 cm and with a spectrum in range of frequencies of drift waves has been observed in the PLT discharge with scattering of microwaves.
Journal ArticleDOI
Microwave Scattering Due to Acoustic-Ion-Plasma-Wave Instability
V. Arunasalam,Sanborn C. Brown +1 more
TL;DR: In this article, an experimental study of microwave scattering from nonequilibrium plasmas in which the electrons had a large steady drift velocity with respect to the ions was presented, and the experimental results indicate that the nonlinear effects are relatively weak.
Journal ArticleDOI
Microwave scattering from unstable electron plasma waves.
TL;DR: In this article, an experimental study of the scattering of microwaves by the density fluctuations due to electron plasma-wave instability in a beam-plasma system was presented, and the results were in agreement with the general predictions of the Shapiro and Drummond and Pines nonlinear theories of plasma oscillations.