1998A&A...334.1112J

We have investigated loop-top kernels of the soft X-ray emission seen in the Yohkoh Soft X-ray Telescope (SXT) images. Detailed comparison of the observations from various Yohkoh instruments shows that these kernels contain two kinds of flare plasma: a cooler (∼10MK) and a hotter (∼20MK) one. The cooler plasma plays a dominant role in the emission recorded by the SXT and the hotter plasma is responsible for the Fe XXV emission and the emission recorded by Hard X-ray Telescope 14-23keV band during the post-impulsive phase of a flare. We argue that the best model, which is in agreement with the above observational results, is a turbulent model of a flare loop-top kernel. The magnetic field is tangled in the kernel and a number of transient current sheets occur there. The hotter (∼20MK) plasma is contained in the current sheets and they are surrounded by the cooler (∼10MK) plasma. The turbulent model of the flare loop-top kernel also allows us to explain why the kernels are brighter than the ``legs'' connecting them with the chromosphere.