With warnings of fuel shortages and the realisation that renewable energy sources are not cable of supporting the growing need for energy, many are asking ‘When will we be able to harness nuclear fusion?’. In this essay I will outline the progress of nuclear fusion so far, and discuss future projects that will help me decide on the current situation regarding nuclear power.
Why Fusion?
Nuclear fusion in simple terms is the combination of two small nuclei into a larger nuclei and a release of energy. The main reaction that will be used in the first reactors will combine deuterium and tritium. Deuterium is found in water, and tritium can be bred through the use of lithium which is abundant in the earth’s crust. This makes the fuel for nuclear
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A toroidal magnetic field is one that runs in a circle, the same direction as the plasma will flow, and a poloidal field coils around the outside on the torus shape as shown. Since magnetic fields lines are vectors, the resultant vector is shown as the blue line in this diagram. In this design the toroidal field is produced by a series of coils that wrap around the torus shape, much like a solenoid that has been wrapped into a circle. However the poloidal field is created by driving a toroidal current through the plasma, which creates a magnetic field. These magnetic fields contain the plasma, not allowing heat loss through the touching of plasma and walls of the tokamak. This is done as charged particles will rotate around magnetic field lines perpetually, so if the magnetic field lines are circular as in this case then the particles will rotate indefinitely. These magnetic fields also increase the density of the plasma, which in turn increases the probability of reactions. The main limitation to this design is the strength of the magnetic field that can be created in the Tokamak. This has improved significantly since the creation of the tokamak as superconducting magnets have been created, which have virtually no resistance so field strengths of 16 Tesla can be created, 3000 times stronger than a fridge magnet. …show more content…
This method uses the principle that a current will dissipate heat when passing through a resistor. So a large current is induced in the plasma through magnetic induction (same current that produces the poloidal field), this current then increases the temperature of the plasma. However the main limitation of this method is that the resistivity of the plasma decreases as the temperature of the plasma increases, therefore there is an upper limit on the temperatures that can be reached by these methods, usually around 20-30 million Kelvin. Again this also has limits on the amount of current that can be induced in the plasma, so other methods have to be used after this initial rise in