Magnetic reconnection is considered to play a key role in the energy release processes of astrophysical plasmas, therefore in order to expand our understanding of the behaviour of plasmas such as the slow solar wind (SSW) we need to identify potential sites for reconnection to occur. For this purpose, solar physicists have developed several models to approximate the weak coronal field of the Sun among which there are potential fields (PFSS), that correspond to the simplest equilibria, and non-linear force-free fields (NLFF), which account for heliospheric current sheets and hence have a higher degree of complexity. One fundamental question to address is how the topology of the structures of the former differs from the one found in the latter.
In this regard, a null finder has been built: this Python code can be run for any magnetic field model and employs a trilinear interpolation and the Newton-Raphson root-finding algorithm to return a list of magnetic null points.
Usage:
null_list = find_nulls(nx,ny,nz, xv,yv,zv, B_x1,B_y1,B_z1, tolerance=None)
This function checks the existence of null points and localize them in the grid
Parameters: nx, ny, nz, xv, yv, zv, B_x1, B_y1, B_z1, tolerence(=None) nx, ny, nz represent the resolution of the grid xv, yv, zv are the coordinate in the x, y and z directions B_x1, B_y1, B_z1 are the components of the B field tolerance sets the exit condition for Newton's method (root finding)
Returns: null_list null_list is a concatenated list of coordinates for all detected nulls