Cecil Moore wrote:

Jim Kelley wrote:
We both know that momentum and energy must be conserved. We just
disagree agree on how nature chooses to do that.

How does nature choose to
reverse the momentum in the wave reflected from a mismatched
source?

The definition is accurate as well as descriptive. As I've explained at
least a dozen times, energy only moves in the direction of transfer.

73, Jim AC6XG