1. The Movement of Charged Particles in a Magnetic FieldBy
Emily Nash
And
Harrison Gray

2. Preview Magnetic fields and their poles Magnetic field of the earth
Solar wind and how the earth’s magnetic field affects it
Taking a look at the force that magnetic fields exert upon electrons by using a cathode ray tube, magnets, and some simple math.

3. Magnetic Fields N S Magnetic Fields are created by moving
charged particles, and only affect moving
charged particles.
Forces between two electric currents is what causes a magnetic force. Two parallel currents flowing in the same direction repel each other, while two parallel currents flowing in opposite directions repel each other. N
When there exists a steady
stream of electrons, a negatively charged particle, an electric
current forms, which produces
a magnetic field.
This force leads to the idea of the north and south poles of a magnetic field. S

4. Magnetic Poles

5. Earth's Magnetic Field N S
The Earth itself is a magnet, with a magnetic north
pole and south pole.
The origin of the Earth’s magnetic field is said to be a result of the dynamo effect, electric currents produced by the rotation of the iron-nickel core. N
The Earth’s magnetic field continually traps moving charged particles coming from the sun. S
High concentrations of these particles within the field are called the Van Allen Radiation belts.
These particles are called cosmic rays, which originally come from the sun.

6. Solar Wind Magnetotail Bow Shock Magnetosheath
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.
Bow Shock
The path of these particles change almost directly as they hit the earth’s magnetosphere at the region called the bow shock.
Magnetosheath
The impact of the solar wind causes
The field lines facing the sun to compress,
While the field lines on the other side stream back to form a
Magnetotail.
Because the charged particles of the rays are deflected around the magnetosheath,
the earth is protected from most of the deadly radiation.

7. contribute to the Van Allen radiation belts.
Solar Wind Cntd
Some solar wind particles, however, do escape the earth’s magnetosphere and
contribute to the Van Allen radiation belts.
When these particles do enter the magnetic field, they go through three motions:
Spiral- the magnetic field changes the path of the particle. The particle, in its new path, is still deflected by the field, and therefore 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 earth’s magnetic field.

8. √
Cathode Ray Tube Cntd.
Since change in energy is the voltage times the charge
then ½mv²=qV
Therefore v= √(2qV/m)
The potential energy
of electrons is converted
to kinetic energy
Electrons are attracted to positively charged
plate. They accelerate towards it and small
percentage escape the plate through small
hole, creating electron beam.
120 Volts
Plate is heated and
electrons boil off.
Velocity= 0
Potential Energy= ½ mv^2
6.3 Volts

9. Cathode Ray Tube

10. Calculating the Velocity of the Electrons
We now know that v= √(2qV/m), so we can now easily find the
velocity of our beam of electrons.
q(charge) of an electron= -1.6•10^-19
V(volts)=120
m(mass) of an electron=9.11•10^-31
Therefore:
v=√(2)(-1.6•10^-19)(120)/(9.11•10^-31)
v=√4.215•10^13
v= m/s

11. therefore the electron
Bending
Electron Beams
Like Solar Wind,
the electrons in the
CRT beam are deflected
when entering a
magnetic field,
therefore the electron
beam “bends.”

12. Bending Electron Beams
In order to predict
the angle at which
the electrons are
deflected, we must
first measure
the force that the
magnetic field inserts
upon the beam
Since acceleration
is equal to v²/r
we can deduce that
F=m(v²/r)
To do this, we use the equation:
F=ma
according to Newton’s second law

13. Calculating the Force of the Magnetic Field
We now know that F=m(v²/r), so we can use this formula to find the force
that the magnetic field exerts upon the electrons.
mass= 9.11•10^-31
velocity= m/s
And we measured the distance of the electron beam from the magnets
to be .075 meters
Therefore F= 9.11•10^-31( ²/.075)