Cosmic Ray Air Shower

What you are seeing: a high-energy cosmic ray (proton, helium, carbon, or iron) enters the upper atmosphere at energy $E_0$ and triggers a cascade. Particles are color-coded: cyan = electromagnetic, red = hadronic, yellow = muons. The right panel shows the Gaisser-Hillas longitudinal profile $N(X)$ with shower maximum marked

Figure 1. 3D cosmic-ray air shower in atmospheric column + Gaisser-Hillas longitudinal profile. Method: Heitler cascade + Gaisser-Hillas N(X).

primaryp

log10 E_0 (eV)18.0

depth progress1.00

animation speed2

zenith angle0°

WHAT TO TRY

Raise the primary energy log10 E_0: the cascade deepens, X_max pushes lower into the atmosphere, and the particle count N_max at shower maximum climbs. More energy means a bigger shower.
Switch the primary (proton to iron): a heavy nucleus fragments higher up and develops faster, so its shower maximum sits higher than a proton of the same energy, the key to mass composition.
Tilt the zenith angle: an inclined shower traverses more atmosphere, spreading the muon footprint wider on the ground, which is what surface detector arrays sample.