What is Fusion?
我们和我们的星球是百万的受益者s ofnuclear fusion reactionstaking place every second inside the sun's core. Without those reactions, we wouldn't have anylightor warmth, and probably no life. A fusion reaction occurs when twoatomsofhydrogencollide to create a largerhelium-4atom, which releases energy. Here's how the process works:
- Two protons combine to form adeuterium atom, apositronand aneutrino.
- A proton and a deuterium atom combine to form a helium-3 atom (two protons with one neutron) and agamma ray.
- Two helium-3 atoms combine to form a helium-4 (two protons and two neutrons) and two protons.
Fusion can only occur insuper-heated environmentsmeasuring in the millions of degrees.Stars, which are made of plasma, are the only natural objects that are hot enough to create fusion reactions. Plasma, often referred to as the fourth state of matter, isionized gasmade of atoms stripped of some electrons. Fusion reactions are responsible for creating 85 percent of the sun's energy.
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The high level of heat required to create this type of plasma makes it impossible to contain the components in any known material. However, plasma is a good conductor of electricity, which makes it possible to be held, guided and accelerated usingmagnetic fields. This is the basis for creating a fusion-powered spacecraft, which NASA believes is achievable within 25 years. In the next section, we will look at specific fusion engine projects in development.