IBS and bunch lengthening due to impedance
Posted: 22 Mar 2024, 03:02
Hello
I've been trying to setup ibsEmittance and haissinski codes to find beam parameters with consideration of combined effects of IBS and impedance. I see that it has been done before, but I need some advice.
In paper it's said that ibsEmittance code is used to abtain energy spread to use it in Haissinski solver. The latter solves for the bunch length using the wakefield. Iterating between the two codes converges to the solution.
1. I begin iteration with ibsEmittance.
2. I put new energy spread in twi file for Haissinski solver to use
3. Run solver to find new beam length. twi file has energy spread from IBS and I'm assigning length from ibs solver.
For the next iteration I put in ibsEmittance new total emittance, energy spread and length from previous iteration step. But there is no convergence.
Will it be correct to put RF parameters in haissinski code instead of length with ibs?
What am I missing?
I've been trying to setup ibsEmittance and haissinski codes to find beam parameters with consideration of combined effects of IBS and impedance. I see that it has been done before, but I need some advice.
In paper it's said that ibsEmittance code is used to abtain energy spread to use it in Haissinski solver. The latter solves for the bunch length using the wakefield. Iterating between the two codes converges to the solution.
1. I begin iteration with ibsEmittance.
Code: Select all
ibsEmittance $twi_file $ibs_file -charge=$charge -emitInput=$ex0 -deltaInput=$sigma_e -coupling=$ratio -length=$sigma_s -noWarning
Code: Select all
sddsprocess $twi_file_new -redefine=parameter,Sdelta0,$sigma_e -noWarnings
Code: Select all
haissinski $twi_file_new $pwd_file -model=Zn=$Zn,R=$R -bunchCurrent=$I -outputLastStepOnly \
-length=$sigma_t -integrationParameters=deltaTime=$deltaTime,points=4000,iterations=1000,fraction=0.01,tolerance=1e-4
Will it be correct to put RF parameters in haissinski code instead of length with ibs?
What am I missing?