Why in the News?
China’s Experimental Advanced Superconducting Tokamak (EAST) fusion reactor has achieved stable plasma densities 30 to 65 percent higher than the Greenwald limit, overcoming a decades old constraint in nuclear fusion research.
About Greenwald Limit
- The Greenwald limit is a theoretical upper limit on plasma density in a tokamak fusion reactor.
- It links the maximum stable plasma density to:
- Plasma current
- Size of the tokamak
- Crossing this limit usually causes plasma instability and sudden collapse.
Why the Greenwald Limit Matters?
- Nuclear fusion requires:
- Very high temperature
- High plasma density
- Sufficient confinement time
- The Greenwald limit restricted how much fuel plasma could be packed into a tokamak.
- It has been a major bottleneck to achieving self sustaining fusion or ignition.
Prelims Pointers
- Greenwald limit applies to tokamak fusion reactors
- Exceeding it traditionally causes plasma instability
- EAST achieved stable plasma beyond this limit
- Breakthrough achieved by plasma wall interaction control
- Important for progress towards fusion ignition and clean energy
| [2016] India is an important member of the ‘International Thermonuclear Experimental Reactor’. If this experiment succeeds, what is the immediate advantage for India?
(a) It can use thorium in place of uranium for power generation (b) It attains a global role in satellite-navigation (c) It can drastically improve the efficiency of its fission reactors in power generation (d) It can build fusion reactors for power generation |
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