Sanborn C. Brown

Kirchhoff's Radiation Law for Plasmas with Non‐Maxwellian Distributions

Calculations are given for the radiation temperature in terms of the average electron energy, to be used for interpreting microwave radiation measurements from plasmas with non‐Maxwellian distributions of electron velocities.

Interaction between Cold Plasmas and Guided Electromagnetic Waves

The interaction between cylindrically symmetric anisotropic plasma column and bounded electro‐magnetic waves is analyzed theoretically. The properties of a cylindrical cavity coaxial with a cold plasma column and a coaxial with a static magnetic field are determined. The shift in the resonant frequency of the cavity‐plasma system is calculated in the high‐electron‐density limit and compared with the numerical solution presented earlier.

The effect of magnetic field on the breakdown of gases at microwave frequencies

The effect of magnetic field on the high frequency breakdown of gases has been studied. The presence of energy resonance and the modification of diffusion are shown experimentally and explained theoretically. An application is made of both the average electron theory and the Boltzmann theory, and the correspondence between these two theories is discussed.

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Methods of Measuring the Properties of Ionized Gases at High Frequencies. III. Measurement of Discharge Admittance and Electron Density

Experimental methods are given for determining the complex admittance and electron density of gas discharges by the use of microwave techniques. Applications are discussed where the discharge is contained in either high or low Q resonant cavities.

Methods of Measuring the Properties of Ionized Gases at High Frequencies. I. Measurements of Q

Experimental methods are given for determining the Q of both high and low Q resonant cavities at microwave frequencies. The emphasis is placed on the practical measurements necessary in determining the properties of ionized gases in the 3‐ and 10‐centimeter wavelength range.

Microwave Measurements of the Radiation Temperature of Plasmas

Radiation‐temperature measurements of positive columns of glow discharges in helium, neon, and hydrogen were compared with calculations and with Langmuir probe measurements of the electron temperature. The microwave‐noise radiation was detected at a frequency of 3000 Mc. The plasma studied was illuminated by a blackbody source of known variable temperature. The blackbody temperature was adjusted until the received noise power became independent of the presence of the unknown plasma. At this point, the temperature of the two radiators is the same, irrespective of the magnitude of the plasma absorptivity.

Cyclotron Radiation from a Hot Plasma

Calculations of the incoherent cyclotron radiation from a hot plasma, based upon the single‐particle model of Trubnikov and Bazhanova are presented. It is shown that the emission at frequencies higher than the blackbody cutoff frequency is not negligible under certain conditions, especially since it is relatively unaffected by proposed reflectors. An approximate absorption coefficient, which is inferred from the calculations, is used to obtain the real part of the refractive index from the Kramers‐Kronig transform for comparison with the results of Drummond and Rosenbluth.

Carbon Dioxide Filled Geiger‐Müller Counters

Efficient detection of the long period carbon isotope, C14, can be achieved when this isotope is oxidized to CO2 gas which may then be used as a Geiger‐Muller counter filling. The special problems which arise in CO2 counters are discussed. Carbon dioxide ions produce undesirable effects which are eliminated by small amounts of CS2. The result of the investigation has been to develop a CO2–CS2 counter which has satisfactory properties for routine studies of C14.

High-Frequency Gas-Discharge Breakdown

A phenomenological description of high-frequency gas-discharge breakdown is given, describing the similarities and differences between these discharges and the more familiar dc type. High-frequency discharge breakdown is controlled by the process of electron diffusion and, besides the theory of its behavior, the physical limitations of tube size, gas pressure, and frequency for this type of breakdown are given. The particular case of hydrogen is cited. The effects of superimposing a small dc field and a magnetic field on the ac field are also discussed.