I was going through a research paper explaining the possible reasons for origin of knee in the cosmic ray spectrum. I came across this statement "nuclei-initiated showers have smaller fluctuations in their development and the sharp cutoff in the primary energy spectrum should not be diluted when transferred to the EAS size spectrum."
Could someone please explain what is nucleus initiated shower and why nucleus initiated showers have lesser fluctuations?
I have gone through a lot websites regarding this question, none seem to explain it satisfactorily.
Thanks for the help.