### Tracking with LRWAKE and ILMATRIX

Posted:

**05 Jan 2022, 10:26**Dear Michael,

I'm studying transverse coupled-bunch instability from long-range resistive-wall wake. In my tracking, I only used ILMATRIX and LRWAKE elements, together with several watch points for each bunch. I calculated the maximum growth rate of each bunch. Then the growth rate is exchanged to 1A.

At first I tracked with only one-particle per bunch, and the result is consistent with the analytic formula, then I increased the number of particles per bunch to 10,000. Then the growth rate of each particle decreases greatly (10 times smaller). But the other parameters are all the same. The exchanged growth rate at 1A is also different when the beam current in tracking is different. Do you have any idea what the reason might be?

Best regards,

Siwei

I'm studying transverse coupled-bunch instability from long-range resistive-wall wake. In my tracking, I only used ILMATRIX and LRWAKE elements, together with several watch points for each bunch. I calculated the maximum growth rate of each bunch. Then the growth rate is exchanged to 1A.

At first I tracked with only one-particle per bunch, and the result is consistent with the analytic formula, then I increased the number of particles per bunch to 10,000. Then the growth rate of each particle decreases greatly (10 times smaller). But the other parameters are all the same. The exchanged growth rate at 1A is also different when the beam current in tracking is different. Do you have any idea what the reason might be?

Best regards,

Siwei