  Long-lived, highly localized structures called palm tree modes (PTM) are
observed in the edge plasma of the JET tokamak. Although PTMs are well
documented, little is known about the mechanisms which produce these
structures. In the case of the PTM, an ELM-postcursor, its genesis is usually
explained by ergodisation of the magnetic field due to edge localized modes and
the appearance of a seed magnetic island which evolves into a PTM later. In
this study we try to invoke a creation mechanism based on the concepts and
observations in edge plasma turbulence. An interesting aspect of plasma
turbulence is the occurrence of coherent, long-lived structures in the
scrape-off-layer (SOL). These localized and magnetic-field-aligned regions with
higher or lower plasma densities are called blobs and holes. Measurements show
that these filaments carry parallel currents. We thus here interpret
ELM-filaments as massive blobs and the interspace between these filaments as
holes. We demonstrate that a forward-modelled closed current filament on a q=3
surface produces similar magnetic fluctuations as measured by the JET in-vessel
magnetic pickup coils if a PTM is present. From that we deduce that if a hole
is captured on a q=3 surface after an ELM-crash, a PTM equivalent signature is
generated. If the ELM-filament itself is captured on a q=4 surface, a signature
equivalent to an outer mode appears.
