The Movement ofCharged Particlesin aMagnetic FieldByEmily NashAndHarrison Gray

Magnetic fields and how they are createdMagnetic field of the earthSolar wind and how the earths magnetic field affects itTaking a look at the force that magnetic fields exert upon electrons by using a cathode ray tube, magnets, and some simple math.

Magnetic Fields are created by movingcharged particles, and only affect movingcharged particles.When there exists a steadystream of electrons, a negatively charged particle, an electriccurrent forms, which producesa magnetic field.Forces between two electric currents is what causes a magnetic force. Two parallel currents flowing in the same direction attract each other, while two parallel currents flowing in opposite directions repel each other.

This force leads to the idea of the north and south poles of a magnetic field.NS

It is possible to create a magnetic field by producing an electric current, or vice versa.When current passes through a coil of wire, it generates a magnetic field along the access of the coil.This is called electromagnetismcurrent

The Earth itself is a magnet, with a magnetic northpole and south pole.SNThe Earths magnetic field continually traps moving charged particles coming from the sun, called solar wind.The origin of the Earths magnetic field is said to be a result of the dynamo effect, electric currents produced by the rotation of the iron-nickel core.High concentrations of these particles within the field are called the Van Allen Radiation belts.

Solar Wind consists of gases comprised of protons, electrons, and ions which hurl towards the earth from the sun at velocities of 450 km/sec or higher.The path of these particles change almost directly as they hit the earths magnetosphere at the region called the bow shock.Because the charged particles of the rays are deflected around the magnetosheath,the earth is protected from most of the deadly radiation. Bow ShockMagnetosheathThe impact of the solar wind causesThe field lines facing the sun to compress,While the field lines on the other side stream back to form aMagnetotail.Magnetotail

Some solar wind particles, however, do escape the earths magnetosphere andcontribute to the Van Allen radiation belts.When these particles do enter the magnetic field, they go through three motions:

Spiral- the particle takes a spiraling motion around a magnetic field line.

Bounce- the particles eventually bounce towards the opposite pole, where they spiral again.

Drift- as the particle continually spirals and bounces, it drift around the magnetic field and is trapped in the magnetosphere.

In order to better understand the motion of particles through a magnetic field,we have conducted an experiment involving creating an electron beam and running it through magnets as a parallel to solar wind entering the earths magnetic field.

6.3 Volts120 VoltsPlate is heated and electrons boil off.Velocity= 0Potential Energy= mv^2Electrons are attracted to positively chargedplate. They accelerate towards it and smallpercentage escape the plate through smallhole, creating electron beam.The potential energyof electrons is convertedto kinetic energySince change in energy is the voltage times the chargethen mv=qVTherefore v= (2qV/m)

We now know that v= (2qV/m), so we can now easily find thevelocity of our beam of electrons. q(charge) of an electron= -1.610^-19V(volts)=120m(mass) of an electron=9.1110^-31 kgTherefore:v=(2)(-1.610^-19)(120)/(9.1110^-31)v=4.21510^13v=64910^6 m/s

In order to predictthe angle at whichthe electrons aredeflected, we mustfirst measurethe force that the magnetic field insertsupon the beamTo do this, we use the equation:F=qvB

Magnetic fieldElectronsLike Solar Wind,the electrons in theCRT beam are deflectedwhen entering a magnetic field,therefore the electron beam bends.The force is alwaysPerpendicular to the magnetic fieldAnd the velocity of the electrons

In order to find the force of the magnetic field, we must first calculate its strenghth.mass= 9.1110^-31 kgvelocity= 6.49210^6 m/sAnd we measured the distance of the electron beam from the magnetsto be .075 metersTherefore B= (9.1110^-31)(6.49210^6)/(1.610^-19)(.075)B=2.77210^-6 teslaSince F=qvB and, according to Newtons second law, F=mv/r, we can deduce thatqvB=mv/rOrB=mv/qrCharge= 1.610^-19 C

Now that we know the strength of the magnetic field at the electron beam, we canCalculate the force which the field exerts upon the electrons.F=qvBF=(64910^6)/(1.610^-19)(2.77210^-6F=2.87910^-18 N

ConclusionThe earths magnetic field and how it shields the earth from solar wind

How to find the force that magnetic field exerts upon charged particles and the strength of the field itself.The movement of charged particles such as solar wind as they enter a magnetic fieldHow to predict the path of a charged particle through a magnetic fieldBasics of Magnetic fields and electromagnetism