The intensity peaks within a solenoid beam are found in a spiral around the line of the beam itself, while a Bessel beam's intensity rises and falls in peaks and troughs at higher distances from the beam's line.
The other two methods rely on specially shaped laser beams - instead of a beam whose intensity peaks at its centre and tails off gradually, the team is investigating two alternatives: solenoid beams and Bessel beams.
According to the automaker, laser lighting can produce a forward beam with an intensity a thousand times greater than conventional LEDs, but with half the energy consumption.
Given the risks of aiming such a powerful beam of high-intensity radiation at an Earth ground station, as well as the cost of building billions of dollars in infrastructure to collect the energy in space, the efficiencies you can get from terrestrial solar power seem a safer bet--at least for now.