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The angular momentum of gas feeding a black hole (BH) is typically misalignedwith respect to the BH spin, resulting in a tilted accretion disk. Rotation ofthe BH drags the surrounding space-time, manifesting as Lense-Thirring torquesthat lead to disk precession and warping. We study these processes bysimulating a thin ($H/r=0.02$), highly tilted ($\mathcal{T}=65^\circ$)accretion disk around a rapidly rotating ($a=0.9375$) BH at extremely highresolutions, which we performed using the general-relativisticmagnetohydrodynamic (GRMHD) code H-AMR. The disk becomes significantly warpedand continuously tears into two individually precessing sub-disks. We find thatmass accretion rates far exceed the standard $\alpha$-viscosity expectations.We identify two novel dissipation mechanisms specific to warped disks that arethe main drivers of accretion, distinct from the local turbulent stresses thatare usually thought to drive accretion. In particular, we identify extremescale height oscillations that occur twice an orbit throughout our disk. Whenthe scale height compresses, `nozzle' shocks form, dissipating orbital energyand driving accretion. Separate from this phenomenon, there is also extremedissipation at the location of the tear. This leads to the formation oflow-angular momentum `streamers' that rain down onto the inner sub-disk,shocking it. The addition of low angular momentum gas to the inner sub-diskcauses it to rapidly accrete, even when it is transiently aligned with the BHspin and thus unwarped. These mechanisms, if general, significantly modify thestandard accretion paradigm. Additionally, they may drive structural changes onmuch shorter timescales than expected in $\alpha$-disks, potentially explainingsome of the extreme variability observed in active galactic nuclei.

Nozzle Shocks, Disk Tearing and Streamers Drive Rapid Accretion in 3D GRMHD Simulations of Warped Thin Disks