Plasma Wakefield/STFC Summer School 2022 Poster

Simulation of short driver bunches. Beams are defined directly within the configuration and beamfiles run through lem.py for diagnostics.

(LCODE configuration takes m/q, but resulting beamfiles are in q/m).

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Driver Density: Long vs Short Proton Bunch

Run Number	Base Configuration	Window Width	Window Length	q/m	Total Weight (pC)	LCODE ampl	LCODE Beam Current	LCODE Beam Length	Beam Length (um)	Energy (approx) (GeV)	Comments
1	short_bunch - DAC	3	10	1.0	-2045.504558	1	-3.6	0.1	3.63	30	Default DAC short_bunch.cfg
2	short_bunch - DAC	3	10	0.00054	-2045.504558	1	-3.6	0.1	3.64	30	Only change made to cfg m/q for protons. Ez plots for 1 and 2 are identical.
3	short_bunch - DAC	3	20	1.0	-2045.504558	1	-3.6	0.1	3.64	30	Plot x-range increases with window length increase.
4	short_bunch - DAC	3	100	1.0	-2045.504558	1	-3.6	0.1	3.63	30	Expecting Ez fall off with distance. Do observe this.
5	short_bunch - DAC	3	100	0.00054	-2045.504558	1	-3.6	0.1	3.64	30	Checking to see if Ez attenuation with distance is different for q/m=1/1836 (proton ). Identical plots.
6	short_bunch - DAC	3	20	0.00054	-2045.504558	-1	-3.6	0.1	3.64	30	Can compare this with run 3 as mass not impacting currently. Identical despite ampl=-1 meaning should be opposite charge. Will set this directly in m/q next.
7	short_bunch - DAC	3	20	1.0	-2045.504558	1	-3.6	0.1	3.63	30	Despite setting m/q=1 in cfg, lem still shows positive and so results identical to run 3.
8	short_bunch - DAC	3	20	1.0	-2045.504558	-1	-3.6	0.1	3.63	30	Keeping m/q as negative and making ampl=-1. Still no change. It seems (from previous knowledge) only changing the sign of the beam current in cfg makes a difference to m/q sign.
9	short_bunch - DAC	3	20	1.0	2045.504558	1	+3.6	0.1	3.63	30	Return to run 3 parameters but set current to positive. Saying q/m is +1 still, but total weight is now positive, suggesting previous runs have been negative species and this is positive.