Strategies to Produce Thermonuclear Plasmas

Strategies to Produce Thermo atomic germ plasmsElrica DegirmenWhat is the reefer European torus and how does it work?The Joint European Torus, or one and only(a) thousand, is a physics adroitness located in the Culham Centre for confederation goose egg in Oxfordshire. plasm physicists and engineers there ar producing thermo thermonuclear germ plasms under magnetised exertion in nine to show that conglutination get-up-and-go is a reliable germ of capability in the future. It is very difficult to do on do principal(prenominal) as in come in for nuclear confederation to happen temperatures millions of degrees above the core of the Sun must be achieved as it is unworkable to gravitationally confine the blood plasma (CEA, 2001) which is the way it happens in stars.A plasma is define as a quasi-neutral ionised gas, and because it is charged, it tail assembly be manipulated by electric and magnetic work of honors (Suplee, 2009).The History of the Joint European Torus spirts history started in 1970 when the Council of the European Community decided to transport on a spinal fusion research programme and wee a European fusion device. After three years in 1973, the designs of JET were being drawn up and in 1977 the Culham site was chosen to build JET and construction work began. It then started operation in 1983 (United kingdom Atomic faculty Authority, 2012). The 9th of November 1991 is a particularly important date in the history of nuclear fusion as this was when the Preliminary Tritium Experiment achieved the domains maiden controlled squirt of fusion magnate (ITER Organization, 2014).What is nuclear fusion?Nuclear fusion is what creators the sun and it involves dickens nuclei fusing unitedly under natural temperatures and pressures. When this response occurs, aptitude is released from Einsteins energy-mass equivalence equation This is because the gist of the masses of the individual nucleons before fusing is greater th an the sum of the masses of the nuclei when they open fused. This leads to a mass defect and due to the conservation of energy a loss in mass is compensated through the release of energy.With regards to nuclear fusion, a lot of energy is released, especially when analysed with nuclear fission. We can comp ar the energy outputs of both nuclear processes through the concept of binding energy. hold fast energy is the amount of energy needful to either remove individually nucleon from each another(prenominal) within the nucleus or the energy needful to fuse the same number of nucleons to form the nucleus of an atom. Looking at the binding energy per nucleon for the elements, we can see which are the most enduring elements (they have the highest binding energy per nucleon) and see which processes (fission or fusion) releases the most energy.It should be noted that the mechanism for nuclear fusion in stars is different compared to achieving nuclear fusion on earth. In stars, the hydrogen atoms are fused in concert due to the extreme pressures as there is such a elephantine quantity of stellar material. An example of one of the main nuclear cycles that puzzle taper in stars is the Proton-Proton Chain which happens in stars with the same mass as our Sun or less (The University of Tennessee). The main re turn of eventsion is the first-year misuse where it converts hydrogen and deuterium into helium and emits a gamma ray as follows (Case Western Reserve University)These pressures, as well as the high temperatures, and the make of gravitational confinement means that the hydrogen atoms, which would normally repel one another due to their positive charges at the centres of their nuclei, are able to drown the degree Celsius barrier, and therefore the strong force is able to attract these nuclei together releasing vast amounts of energy and producing helium in the first place. The Coulomb barrier is the energy that is needed for the electrical repulsion to be scourge in order for the strong nuclear force to take place in order for the nuclei to fuse together (HyperPhysics).Here on earth, it is impossible to gravitationally confine magnanimous amounts of plasma, therefore physicists have developed two main methods for achieving nuclear fusion (for the purposes of civilian energy) inertial confinement and magnetic confinement (CEA, 2001). Another facility, the National Ignition Facility in Liver more(prenominal), calcium uses inertial confinement and this involves the use of lasers.However, JET is concerned with magnetic confinement and, as the name suggests, it involves magnets with a reactor find outd as a torus or as a hollow doughnut. The Russian physicist Andrei Sakharov first came up with the idea of a tokamak as it was considered the most optimal shape to successfully confine a plasma using magnetic field.In terms of magnetic confinement, for nuclear fusion to occur (this is called ignition) three main properties of the plasm a must fulfil certain conditions. This is named the Lawson criterion after it was first proposed by John D. Lawson in 1955. The Lawson criterion states that the triple product of plasma density, confinement time, and the plasma temperature must fulfil this equation for a deuterium-tritium reaction (Irvine, 2011)Where is the plasma density, is the plasma temperature and is the confinement time.Although a lot of energy is needed to overcome the Coulomb barrier and initiate the fusion process, the large energy yield is the reason why research at JET and at other institutes is still ongoing (HyperPhysics). The most common fusion reaction to be studied nowadays and the one that physicists at JET are looking into particularly is the deuterium-tritium, or D-T, reaction. Deuterium and tritium are isotopes of hydrogen. It is as follows (HyperPhysics)Plasma heatingWithin the tokamak, the plasma current is induced by a transformer. The central iron transformer core acts as the primary windin g, and this is situated in the hole of the tokamak reactor, and the plasma acts as the secondary winding. The plasma can act as a secondary winding because it is electrically-charged and therefore acts as a conductor. The alternating current that is supplied to the central magnetic coil induces a ever-changing magnetic field and this is used to control the plasma. This turns a heating exploit called Ohmic heating. Thus induced current causes heating which in addition happens in conventional transformers as well.Neutral-beam injection involves the introducing high- former atoms into the magnetically-confined plasma when it is already ohmically heated. These atoms are ionised as they pass through the plasma and therefore are also controlled by the magnetic field present. They then become high-energy ions and as a result, they transfer some of their energy to the plasma particles in repeated collisions. This increase in the number of collisions increases the average translational e nergizing energy associated with these ions and thence increases the temperature of the plasma overall.Furthermore, radio frequency heating is also used to heat the plasma. This is generated through induction high-frequency oscillating currents in the plasma by external coils. There are parts of the plasma where the energy absorption is high and the frequencies are chosen to match the frequencies of these regions. This is called resonance and it allows large amounts of precedent to be transferred to the plasma.All of these ways of heating the plasma are important as not one single method can produce the necessary temperatures of 100 million degrees Celsius (United earth Atomic Energy Authority, 2012), which is required in magnetic confinement (United Kingdom Atomic Energy Authority, 2012).Confining the plasmaThe main purpose of the tokamak in JET is to magnetically confine the plasma with the help of the device called a tokamak which is a Russian acronym for a torus-shaped magnet ic chamber (European Joint Undertaking for ITER and the Development of uniting Energy (Fusion for Energy), 2013). In order to successfully confine the plasma, the magnetic field lines must move around the torus in a spiraling shape generated by toroidal and poloidal fields.The diagram above is useful in explaining two key concepts in plasma physics the toroidal field and the poloidal field. The toroidal field is represented by the blue line and it is the magnetic field that travels around the torus in circles. The poloidal field is represented by the red arrow and it travels in circles perpendicular to the toroidal field.Both of these fields differ in the way they are produced as well in their direction of travel. The toroidal field is produced by electromagnets which surround the torus, and the poloidal field is generated as a result of the toroidal electric current that follows inside the plasma with the help of a second set of electromagnets (Wikipedia, 2014).Energy productionA t the moment, JET can only produce around 70% of the power needed to heat the plasma in the first place (Mlyn, 2007). However, a new tokamak called ITER is being built in Cadarache and developed in order to develop the technologies and obtain the knowledge necessary to built fusion power stations capable of producing more energy out than in (European Joint Undertaking for ITER and the Development of Fusion Energy (Fusion for Energy), 2013). Energy production from fusion is a promising idea as a fusion reaction, in comparison to the combustion of fossil fuels, is four times more energetic, thus more energy can be produced from very small quantities of deuterium and tritium (ITER Organization, 2014).In practical terms, in order to produce 1000MW of electricity, 2.4 million tonnes of burn would be needed each year for a coal-fired power station, provided only 125kg each of deuterium and tritium per year would be needed to produce the same amount of energy (ITER Organization, 2014).T he futureFrom the research conducted at JET, it was homely to physicists that a bigger tokamak must be built in order to break-even and hopefully obtain a greater energy output than input. To reiterate, this tokamak is cognize as ITER and is currently built in the south of France. Even then, ITER is not being built specifically for energy production and it is only until show will be built that it can be demonstrated to the cosmea that it is possible to harness the power of nuclear fusion on energy. presentment is expected to be running sometime during the 2030s and an actual fusion power plant to be running by 2050 (EFDA, 2014). However, due to inevitable geopolitical issues and financial constraints, there is every possibility that these dates may be pushed in advance into the future. Even so it was in 1905 when Einstein first formulated the mass-energy equivalence relation, it was in 1920 when Eddington first discovered how stars produced energy, it was in 1927 when Langmuir gave plasma its name and thus plasma physics was born (Mlyn, 2007) and there have been many other milestones within plasma physics since then that even if the dates fusion civilian energy is pushed forward by a couple of decades or more it will not mean anything in the long term as man will finally be able to learn how to release it and use it for his service as Eddington said. Irrespective of when the production of fusion energy will occur, JET will have been a cornerstone in the history of fusion energy and plasma physics as experiments at JET have made us closer and closer to ignition. The near step is to build the next series of tokamaks and finally the fusion power plant.Works CitedCase Western Reserve University. (n.d.). The Proton-Proton Chain. Retrieved January 18, 2014, from http//burro.cwru.edu/Academics/Astr221/StarPhys/ppchain.htmlCEA. (2001). Retrieved January 16, 2014, from http//www-fusion-magnetique.cea.fr/gb/fusion/principes/principes02.htmEFDA. (2014). Fusion. R etrieved January 18, 2014, from http//www.efda.org/fusion/European Joint Undertaking for ITER and the Development of Fusion Energy (Fusion for Energy). (2013). oftentimes Asked Questions. Retrieved January 17, 2014, from http//fusionforenergy.europa.eu/faq/a7European Joint Undertaking for ITER and the Development of Fusion Energy (Fusion for Energy). (2013). What is Fusion? Retrieved January 16, 2014, from http//fusionforenergy.europa.eu/understandingfusion/HyperPhysics. (n.d.). Coulomb Barrier for Fusion. Retrieved January 18, 2014, from http//hyperphysics.phy-astr.gsu.edu/hbase/nucene/coubar.htmlHyperPhysics. (n.d.). Nuclear Fusion. Retrieved January 17, 2014, from http//hyperphysics.phy-astr.gsu.edu/hbase/nucene/fusion.htmlIrvine, M. (2011). Nuclear Power A real Short Introduction. New York Oxford University Press Inc.ITER Organization. (2014). Fueling the Fusion Reaction. Retrieved January 17, 2014, from http//www.iter.org/sci/fusionfuelsITER Organization. (2014). Progress in Fusion. Retrieved January 16, 2014, from http//www.iter.org/sci/beyonditerMlyn, J. (2007). Focus On JET. Prague Association EURATOM-IPP.CR.Suplee, C. (2009). The Plasma Universe. Cambridge Cambridge University Press.The University of Tennessee. (n.d.). The Proton-Proton Chain. Retrieved January 18, 2014, from http//csep10.phys.utk.edu/astr162/lect/energy/ppchain.htmlUnited Kingdom Atomic Energy Authority. (2012). JET. Retrieved January 16, 2014, from http//www.ccfe.ac.uk/JET.aspxUnited Kingdom Atomic Energy Authority. (2012). The Tokamak. Retrieved January 16, 2014, from http//www.ccfe.ac.uk/Tokamak.aspxWikipedia. (2014). Tokamak. Retrieved January 16, 2014, from http//en.wikipedia.org/wiki/Tokamak