Suppressed cascade efficiency by Hall effects in magnetohydrodynamic turbulence

Magnetohydrodynamic turbulence with Hall effects is ubiquitous in heliophysics and plasma physics. Direct numerical simulations reveal that, when the forcing scale is comparable to the ion inertial scale, the Hall effects induce remarkable cross-helicity. It then suppresses the cascade efficiency, leading to the accumulation of large-scale magnetic energy and helicity. The process is accompanied by the disruption of current sheets through the entrainment by vortex tubes or the excitation of whistler waves. Using the solar wind data from the Parker Solar Probe, the numerical findings are separately confirmed. These findings provide new insights into the emergence of large-scale solar wind turbulence driven by helical fields and Hall effects.