A new approach of the segregation between high-Fip (First ionisation p
otential) and low-Fip elements in the solar chromospheric plateau is p
roposed. Magnetic fields emerging from the photosphere up to the chrom
osphere and corona can lift up enough low-Fip elements to explain loca
lly their observed overabundances. While the magnetic field rises in t
his partially ionised medium, the electrons become trapped along the r
ising magnetic lines. Protons and ionised heavy (low-Fip) elements fol
low due to the induced electric field. The whole bulk of chromospheric
gas is eventually brought up due to collisions and charge-exchange pr
ocesses. The time delay between the motion of the ionised atoms and th
e motion of the whole gas is however sufficient for ions to accumulate
in a small frontward layer, in which the chemical composition becomes
of ''coronal type'' namely with an overabundance of low-Fip elements.
Local overabundances of low-Fip elements are obtained without any mas
s bias and within short enough time scales. Helium is expected to be s
lightly depleted compared to hydrogen as observed. We present here pre
liminary computations using the homogeneous and static chromospheric m
odels of Vernazza, Avrett and Loeser 1981. Complete dynamical models s
hould be studied in the future, according to the various coronal sites
. The present results seem promising enough to motivate further comput
ations.