The Thomas-Fermi wavevector relates to the damping of an electric field caused by build up of carriers around an impurity (screening). But I cant understand it's physical meaning. Wiki states "Thomas–Fermi screening is the limit of the Lindhard formula when the wavevector (the reciprocal of the length-scale of interest) is much smaller than the fermi wavevector, i.e. the long-distance limit." So it applies when the wave vector is much smaller than the fermi wavevector, but I'm trying to visualise a physical meaning of what the Thomas-Fermi wavevector actually is. Any ideas would really be appreciated.