Experimental Advanced Superconducting Tokamak
The Experimental Advanced Superconducting Tokamak, internal designation HT-7U, is an experimental superconducting tokamak magnetic fusion energy reactor in Hefei, China. The Hefei Institutes of Physical Science is conducting the experiment for the Chinese Academy of Sciences. It has operated since 2006.
It is the first tokamak to employ superconducting toroidal and poloidal magnets. It aims for plasma pulses of up to 1000 seconds.
History
EAST followed China's first superconducting tokamak device, dubbed HT-7, built by the Institute of Plasma Physics in partnership with Russia in the early 1990s.The project was proposed in 1996 and approved in 1998. According to a 2003 schedule, buildings and site facilities were to be constructed by 2003. Tokamak assembly was to take place from 2003 through 2005.
Construction was completed in March 2006 and on September 28, 2006, "first plasma" was achieved.
According to official reports, the project's budget is CNY ¥300 million, some 1/15 to 1/20 the cost of a comparable reactor built in other countries.
Phase I
On September 28, 2006, first plasma was achieved—the first test lasted nearly three seconds, and generated an electrical current of 200 kiloamperes.By Jan 2007 "the reactor created a plasma lasting nearly five seconds and generating an electrical current of 500 kilo amperes".
On November 7, 2010, EAST achieved its first H-mode plasma by LHW alone.
In May 2011, EAST became the first tokamak to successfully sustain H-Mode plasma for over 30 seconds at ~50 million Kelvin.
Phase II
On November 29, 2011, The ribbon-cutting ceremony for EAST auxiliary heating system project was held, signifying EAST's entering of “Phase-II”.On May 19, 2014, after nearly 20-month-long upgrading break since September 2012, EAST was ready for the first round of experiments in 2014.
By May 2015, EAST was reporting 1 MA currents, and H-mode for 6.4 seconds.
In February, 2016, a plasma pulse was maintained for a record 102 seconds at ~50 million Kelvin. Plasma current of 400kA and a density of about 2.4 x 1019/m3 with slowly increasing temperature.
On November 2, 2016, EAST became the first tokamak to successfully sustain H-Mode plasma for over a minute at ~50 million °C.
On July 3, 2017, EAST became the first tokamak to successfully sustain H-Mode plasma for over 100 seconds at ~50 million °C.
On November 12, 2018, EAST reached a milestone of 100 million °C.
Physics objectives
China is a member of the ITER consortium, and EAST is a testbed for ITER technologies.EAST was designed to test:
- Superconducting Niobium-titanium poloidal field magnets, making it the first tokamak with superconducting toroidal and poloidal magnets
- Non-inductive current drive
- Pulses of up to 102 seconds with 0.5 MA plasma current
- Schemes for controlling plasma instabilities through real-time diagnostics
- Materials for diverters and plasma facing components
- Operation with βN = 2 and confinement factor H89 > 2
Tokamak parameters
| Toroidal field, Bt | 3.5 T |
| Plasma current, IP | 1.0 MA |
| Major radius, R0 | 1.85 m |
| Minor radius, a | 0.45 m |
| Aspect ratio, R/a | 4.11 |
| Elongation, κ | 1.6–2 |
| Triangularity, δ | 0.6–0.8 |
| Ion cyclotron resonance heating | 3 MW |
| Lower hybrid current drive | 4 MW |
| Electron cyclotron resonance heating | None currently |
| Neutral beam injection | None currently |
| Pulse length | 1–1000 s |
| Configuration | Double-null divertor Pump limiter Single null divertor |