Influence of a magnetic narrow region on the propagation of Type II spicules into the solar corona

In this paper, we study the possible influence of a magnetic narrow region on the propagation of jets with some characteristics of Type II spicules into the solar corona using two approximations: thermo-mechanical (TM) and magnetohydrodynamic (MHD). We motivate the idea of this paper by considering that some advanced 2.5D numerical simulations of radiation MHD of the formation of Type II spicules show the narrowing of the magnetic field lines in the loops where the spicules propagate. In particular, we propose that the magnetic narrow region be described in terms of a magnetic bottle configuration. In the TM approximation, we have found that the magnetic bottle produces that the 9% of the plasma embedded manages to escape the magnetic confinement, in contrast, the remaining 91% returns to the bottom of configuration colliding to the raising plasma and generating a heating process. The heating process could represent a source that maintains the current temperature of the corona. On the other hand, in the MHD approximation, through numerical simulations, we found that it occurs an increase of temperature mainly at the top of the jet, which supports the idea of sectioning the spicule in the TM approximation. Also, in the MHD approximation, we show that the magnetic bottle does not directly affect the propagation of the jet; since the physical conditions of the ideal MHD equations imply that the magnetic field lines are frozen-in with the plasma, and no confinement effect is possible.

Methods
The data for figures 2, 3 and 7 were obtained using a numerical code developed in Python. The figures 9 and 10 were generated with data obtained of the numerical simulations perfomed with the public available MHD Pluto code.