Effects of noise and vibration on commercial helicopter pilots. Results of Phase 1 research Final report

Noise and vibration effects on commercial helicopter pilot safety, performance, and comfor

Plasma oscillations in low pressure gaseous discharges

This is a continuation of work at the U. S. Naval Postgraduate School under Professor N. L. Oleson, investigating oscillations in low pressure ionized gases. Druyvesteyn analysis (using electronic methods for obtaining first and second derivatives of probe current versus probe potential) and Langmuir probe techniques, are utilized for the investigation of discharges in Neon, Argon, and Krypton at ten microns pressure. Plasma densities as determined from the positive ion section of the probe current curves, from Druyvesteyn analysis, and from observed electron oscillation frequencies, are compared with oscillation amplitudes. Electron oscillations were not detected throughout the discharge; however, at some positions multiple frequencies were detected. Ion oscillations, detected throughout the discharge, corresponded in magnitude to Langmuir electrostatic sound waves, and peaked in amplitude with electron oscillations.http://www.archive.org/details/plasmaoscillatio00ketcLieutenant, United States Coast GuardLieutenant Commander, Civil Engineer Corp