DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
Login | Review | Submit | Logout | Help
Questions about this website? Contact Andrew LeBlanc Questions about ROF? Contact Chuck Greenfield
| Title | 303: RF sustained QH-mode | ||
| Name: | Keith Burrell ( |
Affiliation: | General Atomics |
| Research Area: | ELM Control & Pedestal Physics | Presentation time: | Not requested | Co-Author(s): | R.D. Stambaugh |
| Description: | Investigate whether beam injection is essential in sustaining a
QH-mode plasma. The experiment will switch from all neutral beam injection to ECH during the quiescent phase. If the plasma survives in QH-mode for a time long compared to the fast ion slowing down time in the plasma edge, then we will be able to conclude that beam injection is not necessary for sustainment of the QH-mode and fast ion physics at the plasma edge plays no role in QH-mode | ||
| Experimental Approach/Plan: | The plasma used here will be based on 128502, a high triangularity,
double-null QH-mode with reversed Ip. Neutral beam injection will be used to create the QH-mode and sustain it until about 3000 ms into the shot. At this point, the beams will be turned off and ECH will be used. We will need at least five gyrotrons to obtain the needed power. If QH-mode can be sustained for significant periods of time, neutral beam blips will be used during the RF phase of subsequent shots to obtain complete ion temperature profiles. | ||
| Background: | A key question for QH-mode plasmas is the role of counter injection
and beam injection in general. We know from experiments in the 2003 campaign that QH-mode can be created and sustained with right sources only, which indicates that fast ion orbit loss is not essential for QH-mode. We will be investigating further in the 2008 campaign whether QH-mode is possible with balanced or dominantly co-injection. Even if we achieve that, we still need to determine whether the presence of fast ions orbiting beyond the separatrix is essential. | ||
| Resource Requirements: | Reverse Ip. 7 NBI sources. 4 gyrotrons | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
Print this page