  The steady-state confinement, beta limit, and divertor heat load are among
the most concerned issues for toroidal confinement of fusion plasmas. In this
work, we show that the negative triangularity tokamak has promising prospects
to address these issues. We first demonstrate that the negative triangularity
tokamak generates the filed line rotation transform more effectively. This
brings bright prospects for the advanced steady-state tokamak scenario. Given
this, the stability and confinement features of negative triangularity tokamak
are investigated. We point out that the negative triangularity configuration
with a broad pressure profile is indeed more unstable for low-n
magnetohydrodynamic modes than the positive triangularity case so that the
H-mode confinement can hardly be achieved in this configuration, where n is the
toroidal mode number. Nevertheless, we found that the negative triangularity
configuration with high bootstrap current fraction, high poloidal beta, and
peaked pressure profiles can achieve higher normalized beta for low-n modes
than the positive triangularity case. In a certain parameter domain, the
normalized beta can reach about twice the extended Troyon limit, while the same
computation indicates that the positive triangularity configuration is indeed
constrained by the Troyon limit. This shows that the negative triangularity
tokamaks are not only favorable for divertor design to avoid the edge localized
modes but also can have promising prospects for advanced steady-state
confinement of fusion plasmas in high beta.
