Background: 600-ish years into the future. Humanity finally managed to make Earth uninhabitable and now lives in space. Some humans shed their flesh bodies and are now reduced to brains, their "bodies" being space ships. I am looking for a futuristic, but still science-based explanation which allows such a spaceship to use an acceleration of around 50g for long periods of time (up to 20 hours), and 100g for a few seconds, in extreme cases, without obviously turning the brain it hosts into mush. My imagination created some sort of rotating sphere filled with an electrically-permeable gel, which turns slowly, with the brain inside it, acting as a cushion, but I am not fully satisfied. Any other ideas?
EDIT: I was asked to provide constraints.
- The device which protects the brain in the spaceship should be rather small, no more than twice the size of a human head.
- The space ship is fusion-powered, therefore plenty of power available, but we need to limit the amount of power the device would use, or make the power usage exponentially higher, the higher the protected volume would be.
- „Magical” Forcefields, non-inertial systems or exotic matter usage („MumboJumbonium”, to quote someone) are to be avoided.
- Inertial dampeners are OK, as long as there's some drawback attached to them (see constraint 2 as an example) and they have some background explanation (they work and can be used because...?)
- Acceleration in real space/time is a prerequisite. Propulsion methods which avoid acceleration are not allowed in this context.