Source Free and Free Space

1.what is the difference between Source Free and Free Space ?
2.why in Source Free condition
▽‧E＝0
▽‧H＝0

THX

Free space is nothing. Source free means that there are no electric or magnetic poles. You can have a uniform dielectric (which is not free space) but has no embedded electric or magnetic sources.

hi,

when you are going to solve a wave problem, you should consider two important points:

1-each propagated field and wave must have a source.
2-each propagated wave or field will pass through a media.

when propagation media contains nothing(as flatulent said) we say media is free space.

when propagated wave begin in one media and passes through another media we are encountered a wave with out source in latter media.

regards.