Question

What is the best protection against Coronal Mass Ejections from the sun?

Answer 1

For Earth: A strong magnetosphere.
For your electronics: A Faraday cage.

Explanation:

CMEs happen every week or so and usually don't even get close to the Earth, but occasionally they do. When they do CMEs essentially act like EMPs frying circuit boards and the like while damaging Earth's magnetic field.

Right now Earth's magnetosphere is very weak and the CMEs from the sun can be well over 45 million miles in diameter and be travelling millions of miles an hour. Right now "[a] direct hit from a very large CME is a one-in-100-year event according to solar research at NASA and the European Space Agency." 1

We need to figure out how to protect Earth, fast, to say the least.