https://player.vimeo.com/video/750288087?h=f02db09bd4&badge=0&autopause=0&player_id=0&app_id=58479
Enabled by default, the direction for the particles is shown by an arrow in the viewport.
nxRotate icon when Visible in Editor is enabled. The nxRotate icon visually represents the rotation force applied to particles simulated in the scene and will rotate, in the viewport, when the Rotate Speed value is changed during animations.
Accessed by clicking the drop-down arrow to the left of the Visible in Editor parameter.
Use the slider, or manually input a value to change the icon size.
Set as Force, by default.
The alternative is Velocity.