The evolution of the magnetic field from the large-scale dynamo is considered a central feature of the accretion disk around a black hole .
The resulting low-frequency oscillations introduced from the growth and decay of the field strength , along with the change in field orientation , play an integral role in the accretion disk behavior .
Despite the importance of this process and how commonly it is invoked to explain variable features , it still remains poorly understood .
We present a study of the dynamo using a suite of four global , high-resolution , MHD accretion disk simulations .
We systematically vary the scale height ratio and find the large-scale dynamo fails to organize above a scale height ratio of h / r \gtrsim 0.2 .
Using spacetime diagrams of the azimuthal magnetic field , we show the large-scale dynamo is well-ordered in the thinner accretion disk models , but fails to develop the characteristic “ butterfly ” pattern when the scale height ratio is increased , a feature which is also reflected in the power spectra .
Additionally , we calculate the dynamo \alpha -parameter and generate synthetic light curves .
Using an emission proxy , we find the disks have markedly different characters as stochastic photometric fluctuations have a larger amplitude when the dynamo is unordered .