can greatly complicate the rollover of Γ w . Experimental data also demonstrate that
the so-called “closed”, well baffled, divertors have a lower threshold of the upstream
plasma density for detachment (e.g. see [88]).
9.4 Conclusions
As we have discussed, the edge plasma exhibits different nonlinear phenomena
resulting in the formation of macroscopic, strongly radiative and recombining
structures (e.g. MARFE, detached divertor), nonlinear oscillations and bifurcations.
In many cases, atomic physics effects, including impurity and hydrogen radiation,
drive some of these phenomena. Others are associated with the interplay of atomic
physics effects and cross-field plasma transport (including drifts and anomalous
transport) as well as with plasma interactions with the materials of plasma-facing
components. Some of these phenomena (e.g. divertor plasma detachment) can be
affected by magnetic configuration and geometry of plasma-facing components.
Whereas some of these phenomena can be very beneficial for the performance of
future fusion reactors (e.g. divertor plasma detachment can drastically reduce power
and particle loading on divertor targets), others (e.g. MARFE formation close to
separatrix) can result in the degradation of core plasma confinement and the reduction of overall reactor performance.
Even though large progress was made in the understanding of the physics of these
nonlinear phenomena (e.g. divertor plasma detachment), still much more work is
needed for better assessment of edge plasma behavior in future reactors.
References
1. B. Lipschultz, B. LaBombard, E.S. Marmar, M.M. Pickrell, J.L. Terry, R. Watterson,
S.M. Wolfe, Marfe: an edge plasma phenomenon. Nucl. Fusion 24, 977–988 (1984)
2. J. Neuhauser, W. Schneider, R. Wunderlich, Thermal instabilities and poloidal asymmetries in
the tokamak edge plasma. Nucl. Fusion 26, 1679–1692 (1986)
Fig. 9.20 Neutrals
bypassing impurity
radiation region can face
large power available for
neutral ionization
252
9 Physics of Some Edge Plasma Phenomena
the so-called “closed”, well baffled, divertors have a lower threshold of the upstream
plasma density for detachment (e.g. see [88]).
9.4 Conclusions
As we have discussed, the edge plasma exhibits different nonlinear phenomena
resulting in the formation of macroscopic, strongly radiative and recombining
structures (e.g. MARFE, detached divertor), nonlinear oscillations and bifurcations.
In many cases, atomic physics effects, including impurity and hydrogen radiation,
drive some of these phenomena. Others are associated with the interplay of atomic
physics effects and cross-field plasma transport (including drifts and anomalous
transport) as well as with plasma interactions with the materials of plasma-facing
components. Some of these phenomena (e.g. divertor plasma detachment) can be
affected by magnetic configuration and geometry of plasma-facing components.
Whereas some of these phenomena can be very beneficial for the performance of
future fusion reactors (e.g. divertor plasma detachment can drastically reduce power
and particle loading on divertor targets), others (e.g. MARFE formation close to
separatrix) can result in the degradation of core plasma confinement and the reduction of overall reactor performance.
Even though large progress was made in the understanding of the physics of these
nonlinear phenomena (e.g. divertor plasma detachment), still much more work is
needed for better assessment of edge plasma behavior in future reactors.
References
1. B. Lipschultz, B. LaBombard, E.S. Marmar, M.M. Pickrell, J.L. Terry, R. Watterson,
S.M. Wolfe, Marfe: an edge plasma phenomenon. Nucl. Fusion 24, 977–988 (1984)
2. J. Neuhauser, W. Schneider, R. Wunderlich, Thermal instabilities and poloidal asymmetries in
the tokamak edge plasma. Nucl. Fusion 26, 1679–1692 (1986)
Fig. 9.20 Neutrals
bypassing impurity
radiation region can face
large power available for
neutral ionization
252
9 Physics of Some Edge Plasma Phenomena