The magnetosphere of the SUN stops plenty of small SOLID fast moving objects from entering our system and ITS spread over a few hundred BILLION MILES. You confine that field to around the size of our moon it AMPLIFIES INTENSITY AND EFFECTIVE POWER by the square of the distance inverted. (The smaller you make a more powerful field THE MORE INTENSE AND STRONGER it is) A Laser is energy; we have ones that put a 30 foot wide hole through 6 FEET of SOLID STEEL in 30 seconds or less! The lightsabers would also be plasma contained within a magnetic field using some other additional properties (we can almost actually make them using this method; we dont yet have the power supply needed or a way to make a strong enough field let alone a 3dimensional field to the specs of a lightsaber blade, those ARE the only 2 obstacles left.)