Jagged plot when using clip from particles

I am trying to plot a velocity field(right) from particles(left), where I provisionally used box clip from table to points. However, the graph is a bit jagged, and I want it to be smoother, perhaps tweaking something about interpolation. How can I do this?

To clarify, this plot is the x component of velocity along y axis(x = 0.0)

s vel_field

2023_04_21_17_01_49.tar.gz (2.1 MB)