Dimensions
The plasma inside the machine fills a cylinder of space, 7 meters long and 28 centimeters in diameter.[1] The magnetic field varies along this tube. In the center the field is low; reaching (at most) 0.35
Teslas. The field rises to as high as 15 Teslas at the ends.[1] This change in the strength is needed to reflect the particles and get them internally trapped (see: the
magnetic mirror effect).
Heating
The plasma is heated using two methods, simultaneously. The first is
neutral beam injection, where a hot (25 keV), neutral beam of material is shot into the machine at a rate of 5 megawatts.[1] The second is Electron cyclotron resonance heating, where electromagnetic waves are used to heat a plasma, analogous to microwaving it.
Performance
As of 2016, the machine had achieved a plasma trapping
beta of 0.6 for 5 milliseconds.[2] It had reached an electron temperature of 1 keV using the method of
Electron cyclotron resonance heating. It had reached an ion density of 1×1020ions/m3.[1] The machine loses material out of the ends of the mirror [3] but material is replenished at such a rate as to maintain a density inside the machine.[3]
Diagnostics
During any given experiment, operators can choose from at least 15 fusion diagnostics to measure the machines' behavior:[2]
Thomson Scattering
Motional Stark Effect
CX Energy Analysis (2)
Rutherford Ion Scattering
Ion End Loss Analyzer
Microwave Interferometer
Dispersion Interferometer
Diamagnetic Loops
Langmuir Probes
Pyro electric Detectors
RF Probes
Beam Dump Calorimeters
NBI Sec. Electron Detectors
Neutron Detectors
Thermonuclear Proton Detectors
Pictures of the GDT
The structure of the Gas Dynamic Trap, showing the magnets (in red) and two methods of heating the plasma (Neutral beam injection) and (Electron Cyclotron Resonance Heating). Also shown is the magnetic field profile across the machine.[4]
The Gas Dynamic Trap as seen from above.
The location of the Diagnostics used to measure the behavior of the GDT.
References
^
abcdSimonen, Thomas C. (2015-09-25). "Three Game Changing Discoveries: A Simpler Fusion Concept?". Journal of Fusion Energy. 35 (1). Springer Science and Business Media LLC: 63–68.
doi:
10.1007/s10894-015-0017-2.
ISSN0164-0313.
S2CID122088138.
^
abGas Dynamic Trap (GDT). Experiments with Electron Heating. Budker Institute of Nuclear Physics, Novosibirsk State University. Siberian Branch, Russia, 2012, Thomas Simonen