Scientists are developing a fusion machine that could replicate the power of the Sun and could provide the Earth limitless energy.

Physicists at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have created a so-called "star in a jar" in experimental form, which is a miniaturized version of the power of the Sun. It could provide the Earth with safe, clean and nearly limitless energy, ending mankind's dependence on fossil fuels for generating electricity.

According to a press release, the experimental forms of the nuclear fusion device are the compact spherical tokamaks at PPPL and in Culham, UK.

Existing nuclear facilities uses nuclear fission, where energy is generated through splitting the nucleus of an atom. While the process is highly efficient, it could also be very expensive and dangerous due to the radioactive wastes they produce.

On the other hand, nuclear fusion generates electricity by fusing atoms together instead of splitting them, which is safer as it does not produce radioactive wastes.

However, nuclear fusion requires generating temperatures that are "hotter than the Sun." This is where the spherical tokamaks will be used. These are devices that can produce high-pressure plasmas - the extremely heated gas also known as the fourth state of matter that fuels fusion reactions with relatively low and inexpensive magnetic fields.

While traditional tokamaks are bulkier and are shaped like doughnuts, spherical tokamaks are more compact and are shaped like cored apples. Currently, the two most advanced spherical tokamaks in the world are the National Spherical Torus Experiment-Upgrade (NSTX-U) at PPPL and the Mega Ampere Spherical Tokamak (MAST) at the Culham Center for Fusion Energy in the UK.

The tokamaks or fusion reactors could provide the design for possible next steps in fusion energy - a Fusion Nuclear Science Facility (FNSF) that would develop reactor components and produce electricity as a pilot plant for a commercial fusion power station.

"We are opening up new options for future plants," Jonathan Menard, lead author of the study, said in a statement. A detailed proposal for the "jar" is described in a paper published in the journal Nuclear Fusion.