Experimental investigation of the properties of the hot electron rings in the ELMO Bumpy Torus device using hard x-ray diagnostic techniques

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5481788

Hankins, O E

A thorough understanding of the hot electron rings in the ELMO Bumpy Torus Device (EBT) is essential to the bumpy torus concept of plasma production and confinement. The hot electrons are produced via electron cyclotron resonant heating using a 28-GHz cw gyrotron or several 18-GHz klystrons. Measurements of the electron temperature, density, and geometry of the hot and warm components of a hot electron ring were performed for a number of experimental conditions using hard x-ray measurement techniques, diamagnetic flux-pickup loops, and synchrotron-radiation measurement techniques. An axial array of NaI detectors was used to observe x-ray bremsstrahlung energy spectra resulting from collisions between ring electrons and core plasma ions and electrons. Typical hot electron component temperatures and densities for 28 GHz microwave power operation are 350 keV to 450 keV and 0.8 x 10/sup 11/ to 2 x 10/sup 11/ cm/sup -3/, respectively. Typical hot electron component temperatures and densities for 18 GHz microwave power operation are 110 keV to 150 keV and 0.5 x 10/sup 11/ cm/sup -3/, respectively. The total stored energy of a single hot electron ring as measured by diamagnetic flux pickup loops approaches 40 J and is in good agreement with that deduced from hard x-ray measurements. Using the experimental measurements of ring properties and comparing them with theoretical calculations of the critical ring stored energy needed to form a magnetic well or reverse integral(dl/B), it was determined that the hot electron rings in EBT do not possess sufficient stored energy to create a magnetic well and stabilize the core plasma against flute and simple interchange modes.

• Research Organization: North Carolina State Univ., Raleigh (USA)
• OSTI ID: 5481788
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELECTRON RINGS
PLASMA DIAGNOSTICS
ELMO BUMPY TORUS
ENERGY SPECTRA
HARD X RADIATION
NAI DETECTORS
PLASMA MACROINSTABILITIES
STORED ENERGY
SYNCHROTRON RADIATION
BREMSSTRAHLUNG
BUMPY TORI
ELECTROMAGNETIC RADIATION
ELMO DEVICES
ENERGY
INSTABILITY
IONIZING RADIATIONS
MAGNETIC MIRRORS
MEASURING INSTRUMENTS
OPEN PLASMA DEVICES
PHYSICAL PROPERTIES
PLASMA INSTABILITY
RADIATION DETECTORS
RADIATIONS
SCINTILLATION COUNTERS
SOLID SCINTILLATION DETECTORS
SPECTRA
THERMODYNAMIC PROPERTIES
THERMONUCLEAR DEVICES
X RADIATION
700102* - Fusion Energy- Plasma Research- Diagnostics
700101 - Fusion Energy- Plasma Research- Confinement
Heating
& Production