Cobalt salted hydrogen bombs are one fairly plausible route - how many and how large they&#x27;d need to be is another question.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Cobalt_bomb" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Cobalt_bomb</a><p>[Of course, they don&#x27;t exist at the moment - but they wouldn&#x27;t be that difficult to make as one advantage of a Doomsday bomb is that you don&#x27;t need to deliver it so it can be made as large as you want through staging].