  We analyse the condensation of closed string tachyons on the $C/Z_N$
orbifold. We construct the potential for the tachyons upto the quartic
interaction term in the large $N$ limit. In this limit there are near marginal
tachyons. The quartic coupling for these tachyons is calculated by subtracting
from the string theory amplitude for the tachyons, the contributions from the
massless exchanges, computed from the effective field theory. We argue that
higher point interaction terms are are also of the same order in 1/N as the
quartic term and are necessary for existence of the minimum of the tachyon
potential that is consistent with earlier analysis.
