The region of space behind a superluminally travelling warp bubble is almost entirely devoid of forward travelling particles, however it contains a sparse distribution of particles with greatly reduced energy. Meanwhile the region of space infront of a ship decelerating from superluminal velocity to subluminal velocity is blasted with a concentrated beam of extremely high energy particles.
These results suggest that any ship using an Alcubierre warp drive carrying people would need shielding to protect them from potential dangerously blueshifted particles during the journey, and any people at the destination would be gamma ray and high energy particle blasted into oblivion due to the extreme blueshifts for P+ region particles. While in one way journeys particles travelling towards the origin are potentially dangerously blueshifted, their supposed distance from the origin would render them too sparse to be of major concern by the time they reached the origin.
Of course if you were using this as a weapon then this problem is a feature. The blasting of radiation in front would seem to be an issue with any warp bubble approach. Although anybody that can travel at near light speeds or at superluminal speeds has a lot of power from any kinetic weapons. E=MC^2 so any mass at near light speed is kinetic energy that is several times fusion weapon power because of more efficient matter to energy conversion.
Space is not just an empty void between point A and point B… rather, it’s full of particles that have mass (as well as some that do not.) What the research team — led by Brendan McMonigal, Geraint Lewis, and Philip O’Byrne — has found is that these particles can get “swept up” into the warp bubble and focused into regions before and behind the ship, as well as within the warp bubble itself.
Another thing the team found is that the amount of energy released is dependent on the length of the superluminal journey, but there is potentially no limit on its intensity.
“Interestingly, the energy burst released upon arriving at the destination does not have an upper limit,” McMonigal told Universe Today in an email. “You can just keep on traveling for longer and longer distances to increase the energy that will be released as much as you like, one of the odd effects of General Relativity. Unfortunately, even for very short journeys the energy released is so large that you would completely obliterate anything in front of you.”
The Alcubierre warp drive allows a spaceship to travel at an arbitrarily large global velocity by deforming the spacetime in a bubble around the spaceship. Little is known about the interactions between massive particles and the Alcubierre warp drive, or the e ects of an accelerating or decelerating warp bubble. We examine geodesics representative of the paths of null and massive particles with a range of initial velocities from c to c interacting with an Alcubierre warp bubble travelling at a range of globally subluminal and superluminal velocities on both constant and variable velocity paths. The key results for null particles match what would be expected of massive test particles as they approach c. The increase in energy for massive and null particles is calculated in terms of vs, the global ship velocity, and vp, the initial velocity of the particle with respect to the rest frame of the origin/destination of the ship. Particles with positive vp obtain extremely high energy and velocity and become time locked” for the duration of their time in the bubble, experiencing very little proper time between entering and eventually leaving the bubble. When interacting with an accelerating bubble, any particles within the bubble at the time receive a velocity boost that increases or decreases the magnitude of their velocity if the particle is moving towards the front or rear of the bubble respectively. If the bubble is decelerating, the opposite e ect is observed. Thus Eulerian matter is una ected by bubble accelerations/decelerations. The magnitude of the velocity boosts scales with the magnitude of the bubble acceleration/deceleration.