DESIGN, DEVELOPMENT, AND APPLICATION OF A COMPLETE ANALOG PLASMA-DIAGNOSTIC SYSTEM.
D. R. Nordlund, O. P. Breaux · Defense Technical Information Center (DTIC) · 1971
The simple electronic diagnostic system described provides a calibrated oscilloscope display of a Langmuir-probe I-V characteristic, its first- and second-derivative curves, the electron-energy distribution function, and the cumulative electron number density. The system also provides a simple method for determining plasma potential and--if it exists--the electron temperature. Data taken in a low-temperature mercury discharge is compared with data taken by means of the well-known harmonic second-derivative technique. An electron number density of 4.9 x 10 to the 16th power/cubic meter and an electron temperature of 9,700 degrees K found with the new system compare very favorably to values of 4.7 x 10 to the 16th power/cubic meter and 9900 degrees K determined from the harmonic second-derivative data. The system described features more rapid data reduction and lower cost than existing harmonic systems. A detailed design procedure for construction of the accurate differentiators is given. (Author)