.
in a conductor.
.
This seperates into 2 equations: 
and 
. The second equation has solution
of exponentials or linear term for 
. The first equation is solved
by 
, 
, or for , 
. The general solution is a superposition of all
these solutions. 
: 
and 
so we want 
to satisfy 
. Must have 
in order to avoid
the singularity. so 
. Very near to the cornet, you will get only the
lowest order terms contributing. Then 
.