Curvature of magnetic field in plasma turbulence

Magnetic field lines undergo stretch-twist-fold processes in the presence of turbulence. The curvature field, measuring the tangling of the magnetic field lines, is studied in detail here, using both simulations and observations. The probability distribution function (PDF) of the curvature has distinct power-law tails for both high and low limit values. A central finding is that high curvature co-locates with low magnetic field, which gives rise to the power-law tail of PDF at high curvature. The curvature drift term that converts magnetic energy into flow and thermal energy, largely depends on the curvature field behavior, a relationship that helps to explain particle acceleration due to curvature drift. This adds as well to evidence that turbulent effects most likely play an essential role in particle energization since turbulence drives stronger tangled field configurations, and therefore curvature.