[lammps-users] I have a question in indent command.

Dear Users,

I have a cylinder for ions in order not to penetrate into the cylinder.
I am using fix indent command.
Force and Energy formula given in the Mannual are

F(r) = - k (r-R)^2

E = k/3*(r-R)^3

I am curious about the sign of k.
Is k positive if the cylinder repels ions ?

F(r) is attractive inside the cylinder.
I would like to know if this is a typo or not.

Any suggestion is greatly appreciated.
Thank you.

Se Il.

The doc page says: The force is repulsive and F(r) = 0 for r > R.

This means atoms inside the indenter (r < R) are pushed out of
the indenter.