I believe there are two different things that have similar effect.  One
is electrogravitic.  This dates to T.T. Brown in the 50's.  And, two,
the air spike which was tested some time ago, but I have heard little
of it lately.  I believe it was a simple microwave air deflector.

The heat build up on a hypersonic vehicle is enormous, just as the
theoretical calculations predicted.  Various material means of blocking
heat penetration are both experimental and marginal.  Anything
electronic might be better.

It is my belief that the 7000 F. degree heat experienced by the Space
Shuttle is just the beginning.  For a space vehicle returning from a
planetary mission 20,000 degree F. capability is desirable.  A
returning vehicle might not have fuel for an extended retrofire,
necessitating a 100,000+ mph reentry.