Magnetic Fusion Reactors

SYMTRAN - A Time-dependent Symmetric Tandem Mirror Transport Code

“…These results concern two physical phenomena. First, like all fusion reactors, tandem mirror reactors are subject to thermal instability in the burning core, due to runaway alpha production as the ion temperature increases [6]. In tandem mirrors this alpha-driven thermal instability is usually overshadowed by end losses, destabilizing at fixed plug density (as found in Run 1) but stabilized by plug feedback as discussed in Section 5.…”

“…∂(n p /∂t) + (n p /t p ) = S p = n p N b sv (4) n p t p = (n C t ie )[1 -(f i + f e )/ E B ] (5) f i = T e ln(n P /n C ) (6) (f e /T e ) exp (f e /T e ) = t | | /t ee {(2L p /R M L C )(n p 2 /n C ) + n C }{(2L p /R M L C )n p (t | | /t p ) + n C } -1 ª (m i /m e ) 1/2 (T i /T e ) 3/2 (f i /T i ) exp (f i /T i )…”

“…The ambipolar potential on each flux surface is calculated using Eqs. (6) and 7, where Eq. (7) balances end losses of ions and electrons (in the limit of long mean free path).…”

“…First, we note that convergence problems in our earlier steady state code [1] appear to be solved in the time-dependent version. Secondly, we sometimes encounter thermal instability common to all fusion reactors [6]. Criteria for thermal stability are developed that explain the apparent stability of TMX and predict stable regimes for reactors.…”

Tokamak Power Reactor Ignition and Time-Dependent Fractional Power Operation

“…HEAT but the exponent value rang s on each of the tokamak machines examined from leas than -0.3 to about -0.7, and it is this range which is quoted in recent INTOR workshop contributions on the likely range for the exponential contribution to confinement degradation. *5 The PJJEAT ia existing experiments is supplied by NBI primarily, with gome RF heating data. This data fit is…”