Cecil Moore wrote:
John Popelish wrote:

This is the pattern the standing wave function describes. The current
at every point has one of two phases, which are 180 degrees from each
other.

Is this how you see it?

Yes, now which direction is that current flowing?

You deleted the arrows which I drew that showed one possible case. Do
you have some argument with what you deleted?
(I'll replace it, so you don't have to go back to look at it)
(begin paste)

For example, if we took a snapshot of the current, all along the line
at the moment it peaked it might look like thislength of arrow
represents current magnitude, and head shows direction)(view in fixed
width font)

.....--- --- -- - - -- --- --- -- - - --......
hole-------------------50 ohm coax-------------------hole

This is a snapshot of the current all along the line at an instant.

A quarter cycle later, the current would be zero, everywhere.

A half cycle later (than the first snapshot) it would look like this:

.....--- --- -- - - -- --- --- -- - - --......
hole-------------------50 ohm coax-------------------hole
(end paste)

See all those arrows of various length representing current direction
and magnitude? Why do you ask me about something after erasing my answer?

If the source were known to be to the left, would that change
your answer?

For a pure standing wave, there is effectively a source at each end,
so this question is meaningless.