We develop a model of thin turbulent accretion discs supported by magnetic pressure of turbulent magnetic fields .
This applies when the turbulent kinetic and magnetic energy densities are greater than the thermal energy density in the disc .
Whether such discs survive in nature or not remains to be determined , but here we simply demonstrate that self-consistent solutions exist when the \alpha -prescription for the viscous stress , similar to that of the original Shakura–Sunyaev model , is used .
We show that \alpha \sim 1 for the strongly magnetized case and we calculate the radial structure and emission spectra from the disc in the regime when it is optically thick .
Strongly magnetized optically thick discs can apply to the full range of disc radii for objects \la 10 ^ { -2 } of the Eddington luminosity or for the outer parts of discs in higher luminosity sources .
In the limit that the magnetic pressure is equal to the thermal or radiation pressure , our strongly magnetized disc model transforms into the Shakura–Sunyaev model with \alpha = 1 .
Our model produces spectra quite similar to those of standard Shakura–Sunyaev models .
In our comparative study , we also discovered a small discrepancy in the spectral calculations of Shakura & Sunyaev ( 1973 ) .