Whistler wave propagation in the antenna near and far fields in the Naval Research Laboratory Space Physics Simulation Chamber
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375-5346 (United States)
In previous papers, early whistler propagation measurements were presented [W. E. Amatucci et al., IEEE Trans. Plasma Sci. 33, 637 (2005)] as well as antenna impedance measurements [D. D. Blackwell et al., Phys. Plasmas 14, 092106 (2007)] performed in the Naval Research Laboratory Space Physics Simulation Chamber (SPSC). Since that time there have been major upgrades in the experimental capabilities of the laboratory in the form of improvement of both the plasma source and antennas. This has allowed access to plasma parameter space that was previously unattainable, and has resulted in measurements that provide a significantly clearer picture of whistler propagation in the laboratory environment. This paper presents some of the first whistler experimental results from the upgraded SPSC. Whereas previously measurements were limited to measuring the cyclotron resonance cutoff and elliptical polarization indicative of the whistler mode, now it is possible to experimentally plot the dispersion relation itself. The waves are driven and detected using balanced dipole and loop antennas connected to a network analyzer, which measures the amplitude and phase of the wave in two dimensions (r and z). In addition the frequency of the signals is also swept over a range of several hundreds of megahertz, providing a comprehensive picture of the near and far field antenna radiation patterns over a variety of plasma conditions. The magnetic field is varied from a few gauss to 200 G, with the density variable over at least 3 decades from 10{sup 7} to 10{sup 10} cm{sup -3}. The waves are shown to lie on the dispersion surface for whistler waves, with observation of resonance cones in agreement with theoretical predictions. The waves are also observed to propagate without loss of amplitude at higher power, a result in agreement with previous experiments and the notion of ducted whistlers.
- OSTI ID:
- 21344668
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 17; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANTENNAS
CYCLOTRON RESONANCE
DISPERSION RELATIONS
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
EQUIPMENT
INSTABILITY
MAGNETIC FIELDS
NOISE
PLASMA
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PLASMA WAVES
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
RESONANCE
WAVE PROPAGATION
WHISTLER INSTABILITY
WHISTLERS