The young HFA with energy-dispersed beam, small magnetic field rotation was observed upstream of the bow shock.

The energy spread of dispersed beam, adjacent to current sheet was linearly scaled by gyroradius.

Highest number density and pressure of the beam were highest in the current sheet itself.

Velocity distribution and number density of the beam were similar to these values of upstream beam behind the nearest shock.

Upstream moving particles behind the shock provide the most probable source of upstream beam propagating within current sheet.