Diagnostics for mirror machines

This paper is subdivided into three chapters to match three corresponding lectures. The goals of the first chapter are to define the neutral-beam-heated, quasi-d.c. mirror confinement systems under discussion here and to give a general example of mirror diagnostics by listing and very briefly discussing the diagnostics used on the 2XIIB experiment at the Lawrence Livermore Laboratory. The second chapter develops mirror machine diagnostics in more detail, and adds background for a few selected diagnostics of particular importance to mirror machine studies. The third chapter discusses the special diagnostic needs of future mirror machines, with emphasis on diagnostics involving the higher-power neutral beams used with them

Novel neutralized-beam intense neutron source for fusion technology development

We describe a neutralized-beam intense neutron source (NBINS) as a relevant application of fusion technology for the type of high-current ion sources and neutral beamlines now being developed for heating and fueling of magnetic-fusion-energy confinement systems. This near-term application would support parallel development of highly reliable steady-state higher-voltage neutral D/sup 0/ and T/sup 0/ beams and provide a relatively inexpensive source of fusion neutrons for materials testing at up to reactor-like wall conditions. Beam-target examples described incude a 50-A mixed D-T total (ions plus neutrals) space-charge-neutralized beam at 120 keV incident on a liquid Li drive-in target, or a 50-A T/sup 0/ + T/sup +/ space-charge-neutralized beam incident on either a LiD or gas D/sub 2/ target with calculated 14-MeV neutron yields of 2 x 10/sup 15//s, 7 x 10/sup 15//s, or 1.6 x 10/sup 16//s, respectively. The severe local heat loading on the target surface is expected to limit the allowed beam focus and minimum target size to greater than or equal to 25 cm/sup 2/

Time integrated x-ray measurments of the very energetic electron end loss profile in TMX-U

The time-integrated 2-D profile of the thick-target bremsstrahlung produced by energetic end loss electrons has been measured during ECRH operation of TMX-U. Sheets of x-ray film and/or arrays of thermoluminescent dosimeters were placed on the outside of the end tank end wall to measure the relative spatial x-ray profile, with locally added filters of Pb to determine the effective mean x-ray energy. The purpose of this simple survey diagnostic was to allow deduction of the gross features of the ECRH region. The electron source functions needed to fit the x-ray data were modeled for various anchor cell radial distributions mapped along magnetic field lines to the elliptical plasma potential control plates or the Al end walls. The data are generally consistent with (1) major ECR heating in the central 25-cm-diam core, (2) a mean ECRH electron loss energy of 420 keV, and (3) an ECRH coupling efficiency to these hot electrons of greater than or equal to 10%

End cell I and C requirements for operating tandem mirror reactors

The next generation of fusion reactors will be developed to achieve near-ignition conditions and operate in a tritium environment for significant periods of time. Radiation-hardened diagnostic instrumentation must be developed for these reactors. Although neutral beam injection (NBI) will be used for plasma heating and fueling of experimental fusion machines like MFTF-..cap alpha.. + T, it is believed that ion cyclotron resonance heating (ICRH) will be used in future machines for heating the plasma. When rf heating is used, fueling will be accomplished with gas puffing and advanced fuel injectors. End cell coils, NBI, and microwave power injectors are needed to provide adequate confinement. Microwave power and NBI control the electostatic potentials of the plug and barrier. Low-frequency rf power provides drift pump control of the ions so that they are lost radially, enhancing the use of direct converters that collect the axially flowing electrons. Direct or indirect measurements of electrostatic potential barriers, electron density, and temperature appear necessary to control the NBI and microwave power generators. This paper discusses some of the end cell instrumentation and control (I and C) systems believed to be necessary for tandem mirror reactors

Tests and development of duoplasmatron and mutli-aperture heavy ion sources for an RF linac

The goal of the program of ion source development for an rf linac has been to produce currents of up to 100 mA of the heavier gaseous ions such as argon and xenon, of good emittance (.02 ..pi.. cm mr, normalized) and charge state 1/sup +/. Existing facilities and hardware utilized included the 470 kV Bevatron injector, the 750 kV injector for the 50 MeV ESCAR linac, the 80 kV Bevatron test stand, a 20 kV LLL test stand and existing duoplasmatron and CTR sources. A summary of test results is shown