We have developed a numerical MHD model of the propeller candidate star AE Aqr using axisymmetric magneto-hydrodynamic ( MHD ) simulations .
We suggest that AE Aqr is an intermediate polar-type star , where the magnetic field is relatively weak and some kind of an accretion disc may form around the white dwarf .
The star is in the propeller regime , and many of its observational properties are determined by the disc-magnetosphere interaction .
Comparisons of the characteristics of the observed versus modelled AE Aqr star show that the model can explain observational properties of AE Aqr if the magnetic field of the star is B \sim ( 2.8 - 4.2 ) \times 10 ^ { 5 } G. In a representative model , the magnetic field is B \approx 3.3 \times 10 ^ { 5 } G and the time-averaged accretion rate in the disc is 5.5 \times 10 ^ { 16 } g/s .
The star is in the strong propeller regime , where 85 per cent of the disc mass is ejected into conically-shaped winds .
The numerical model explains the rapid spin-down of AE Aqr through the outflow of angular momentum from the surface of the star into the wind .
The model can explain the low accretion rate onto the star if the radiative efficiency of accretion \eta \approx 0.07 .
The energy budget in the outflows , 2 \times 10 ^ { 33 } erg/s , is sufficient for explaining the observed flaring radiation in different wavebands .
The time scale of ejections into the wind matches the short time scale variability in the light-curves of AE Aqr .
Most of the matter is ejected into the wind by the magnetic force , and matter flows into the wind at relatively low velocities , 100 - 700 km/s .
This can explain the predominantly low outflow velocities observed in the tomograms of AE Aqr .