A design study for the ECH launcher for ITER
- General Atomics, San Diego, CA (United States)
- ITER Garching Joint Work Site, Garching bei Muenchen (Germany)
- CompX, Del Mar, CA (United States)
The Design Description Document for ITER calls for 50 MW of electron cyclotron power at a frequency of 170 GHz, upgradeable to 100 MW. This power is intended to heat the plasma from Ohmic temperatures to ignition, in concert with power from some combination of neutral injection and/or ICRF heating. The second major application of ECH power is current drive. In the advanced steady-state scenarios, the total current is 12 to 16 MA, of which 75% is driven by bootstrap effects. The current drive requirement is 2 to 3 MA at a relative minor radius of 0.7, plus a small current near the center of the discharge. ECH power is also used for plasma initiation and startup, using a separate ECH system of two fixed frequencies between 90 to 140 GHz and total power to 6 MW. Suppression or control of MHD instabilities like neoclassical tearing modes, sawteeth, ELMs, and locked modes are also important objectives for the ECH systems. However, the launching and power characteristics of the ECH for these applications is highly specialized. The ability to modulate at high frequency (at least several tens of kHz), the ability to redirect the beams with precision at relatively high speed, and the requirement that the stabilization be carried out at the same time as the bulk heating and current drive imply that separate and specialized ECH systems are needed for the stabilization activities. For example, for stabilization of neoclassical tearing modes current must be driven inside the islands near the q = 2 surface. If this is done near the outboard mid plane, a system with optimized frequency might be much more effective than what could be done with the main 170 GHz system. This paper does not treat the launchers for the stabilization systems.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-94SF20282
- OSTI ID:
- 628998
- Report Number(s):
- GA--A22580; CONF-970405--; ON: DE97008487
- Country of Publication:
- United States
- Language:
- English
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