I wouldn't personally recommend pepper spray.
Not only is there a chance it will be blown back on you by the wind,
but even if it makes it's mark, I think it will merely anger, not stop a criminal.
There are some cool, less than lethal weapons available to the police
like the SAGE weapon. It fires a number of types of rounds, like hard plastic
batons, chemical rounds etc.
However, it is a (very) large weapon that looks like a "street sweeper" shotgun. Your wife is not going to pull it out of her purse and take care of business.
Good tool for the police, though.
Our local police (surprisingly) had the restraint to use it on an
armed man who was acting pretty psychotic and after threatening a public official with a gun, went home and then emerged from his home with a gun.
A hit from the SAGE weapon took all the wind out of him.
That being said, there have been a lot of uses of lethal force compared to that incident. I somehow suspect that this man was given different treatment because he was connected and well heeled.
Lesson learned, don't mess with the police...