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Major
equipment available to facility users:
Diagnostic
Equipment
Fifteen
Digital Oscilloscopes ranging from 2 channel-175 MHz/channel to
4 channel-2 GHz/channel, 6 Stanford digital delay generators (1
ps accuracy), 2 BNC 8 channel pulse generators ( 1 ns accuracy),
1 LeCroy arbitrary waveform generator (10 MHz), 2 Agilent arbitrary
waveform generators (80 MHz), HP 8568B spectrum analyzer, 3 LeCroy
1820A Differential Amplifiers/Filters, Agilent Network Analyzser
(to 180 MHz), 2 four channel Tektronix-Sony 100 MHz optical isolators,
2 microscopes for probe construction (one with micro-manipulators.
Computing
and Networking
The
communications network in the STRB uses a dedicated 10/100/1000
Gbit switch with a direct fiber optic link to the facility office
space next door. The STRB itself is connected to the UCLA
campus backbone by a Cisco 7200 switch. Wireless (A/G) network
connectivity is also provided to the users in both the STRB and
offices. While at UCLA, experimenters can use the data analysis
and visualization systems developed by the local group, as well
as networked workstations, disk farms and the equipment and software
needed to make computer-generated videos and CD's from data acquired
on the LAPD-U.
The
available resources include over three terabytes of centralized
data storage, hosted by a dual-64 bit Linux server. Three Linux
workstations with 1GB RAM and high-end 3D graphics cards are dedicated
to facility users during their stay. In addition, the facility
and local resources include a Sun Ultra-2 workstation, 2 DEC Alpha
workstations with powerstorm graphics boards, 1 SGI Indigo-2,
1 SGI 2 processor Octane with high end graphics (running Maya
for visualization), 6 Windows XP systems (for experiment data
acquisition, automated probe motion, machine state monitoring
and control), 7 Mac computers (one configured for making videos
with 1GB ram, 200 GB disk, with a single-frame accurate Sony Hi-8
recorder, DVD burner, Adobe Premier software, PhotoShop, Illustrator,
Maya, and other graphics software). Workstations have PV-wave,
IDL and AVS for scientific visualization as well as several
language compilers (C, C+, and Fortran), Xerox color laser printer,
slide scanner, and flatbed scanner.
Amplifiers
& Sources for Launching Waves
1
custom built 30 kW amplifier (may be tuned for 200 kHz-5 MHz operation),
1 Velonix 360 high voltage pulser (up to 30 kV pulses, 100 ns rise-time),
1 AR 2500L, 10 kHz-220 MHz, 2.5 kW broadband amplifier 1 AR 2000L,
10 kHz-220 MHz, 2 kW broadband amplifier, 1 AR 200L 1 MHz-200 MHz,
200 W broadband amplifier, 1-250 kW ( 2.5 ms pulse) 9 GHz source.
Lasers
Picture:
50 MW frequency doubled YAG pump laser and SIRAH dye laser.
The pulse stretcher is sown on the left. The laser is focused
into an optical fiber and delivered to the machine.
One
Nd-YAG pumped laser with 7 ns, 150 MW pulse (up to 10 pps) with
a 532-nm Gaussian beam. One tunable dye laser, 1-Watt CW (Coherent
899 driven by an INNOVA Argon ion laser) mounted on an air-isolated
optical bench (Spectra Physics Pro 290). Can operate in the
blue to far red depending upon choice of dye, bandwidth 1 MHz, and
free spectral range 30 GHz. Equipment associated with this
laser is: a confocal spectrum analyzer, New-Focus 7711 Fizeau Wavelength
meter, iodine cell, opto-acoustic light chopper and light detection
phototubes, amplifiers and power supplies. The newest addition
is a pulsed dye laser (10 ns pulse and 100 ns pulse stretcher) 2-12
MW programmable, spectral output from 270-700 nm for LIF photography.
This is coupled with a Cooke Gen III , high speed ( tmin = 3 ns),
(1024X1280 pixel CCD), computer controlled camera with averaging
and background subtraction capabilities. This camera is for
the imaging of planar LIF signals. The laser system is shown
in Fig 6. Both lasers are interfaced to computers and can
be driven by the data acquisition system or used independently.
The
LArge Plasma Device (LAPD)
The
LAPD-II plasma column has a maximum length of 18 meters and a 75-centimeter
diameter. Plasmas of varying length can be explored by segmenting
the device (i.e., inserting a terminating copper end plate at various
axial locations). The confining magnetic field can achieve a steady-state
value of up to 3.5 kG. Ordinarily the magnetic field is uniform,
but it be can varied to generate multiple or single mirror geometries,
magnetic cusps, axial field gradients and other configurations of
scientific interest. The device currently has one cathode and will
soon have two independent cathodes (each in a two meter long, 1.6
m diameter source chamber) which permits the creation of controlled
plasma flows. Each cathode is driven by a 4-Farad capacitor bank
that can supply a total discharge current of 32 kA. The electron
sources are switched by banks of 2.5 kA, 1.5 kV transistors. The
cathodes may be synchronized or operated independently. A pulsed
gas feed system at each end of the device permits the formation
of uniform or non-uniform axial neutral gas profiles that permit
the study of effects associated with ion mass gradients. The equipment
and software needed to make computer-generated videos and CD's from
data acquired on the LAPD-II.
The
length of the plasma column and the radial density profiles can
be tailored to study various physical processes that depend on transverse
or axial gradients in density and temperature. Plasmas will be routinely
available with density in excess of 5x10^12/cm^3 and electron temperatures
in the 10 eV range. The ion temperature will be varied through the
application of 100kW of ICRF power.
The
LAPD-II has unprecedented access. It has eight, 12 cm diameter access
ports between magnets (424 in total) including eight, unique "octo-ports".
The octo-ports have eight, 10 x 40 cm, rectangular openings, which
allow for a nearly unimpeded 360o view of the plasma column. These
ports can be used for visible and microwave tomography, laser fluorescence,
or the insertion of various large antennas or plasma terminating
end plates.
It
will be possible to connect several (up to four), computer-controlled,
probe drive systems at once through any one of 50 adjacent ports
on either side along the machine axis. If the need arises, simultaneously
activated probes could acquire data at several spatial locations
in the plasma volume at once. Probes may be introduced during machine
operation through vacuum interlocks and portable pump-down stations
without disturbing the vacuum system or plasma conditions. Several
pump-down stations comprising a small 200-400 l/s turbo and mechanical
pump, ionization gauges and vacuum fittings enable users to move
instrumentation in and out of the device. The main vacuum system
relies on four turbo pumps with a combined pumping speed of 8000
l/s. Two Stanford residual gas analyzers with computer interfaces
monitor the vacuum and gas evolution during cathode conditioning.
Neutral target gases are admitted with feedback controlled piezoelectric
valves.
The
magnetic coil system consists of 90 pancake magnets placed at 6-inch
intervals along the machine length. The magnets are controlled by
ten separate power supplies, specifically designed for this system.
The power supplies can be controlled manually or by computer, and
allow operation of up to 4.0 kG axial magnetic field with 0.1% current
ripple. The magnet power supplies (4 supplies: 9.6 kA, 40 V; 6 supplies
: 3600 A, 84 V) are fed by a 4.0 megawatt substation acquired for
this project. An additional megawatt of power is available in the
laboratory for general use. The building is unique in its electrical
capabilities; it is designed to accommodate large experiments that
require high power levels. Presently there is 15 MW available in
the building switchyard, and this can be doubled if necessary.
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