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The MovementThe Movementofof
Charged ParticlesCharged Particles
in ain aMagnetic FieldMagnetic Field
ByEmily Nash And
Harrison Gray
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• Magnetic fields and how they are created• Magnetic field of the earth
• Solar wind and how the earth’s magneticfield affects it
• Taking a look at the force that magneticfields exert !on electrons "y sing acathode ray t"e# magnets# and some
sim!le math$
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Magnetic Fields are
created by movingcharged particles,
and only affect
moving
charged particles.
%hen there exists asteadystream of electrons#a negati&ely
charged !article# anelectriccrrent forms#which !rodcesa magnetic field$
'orces "etween two
electric crrents iswhat cases amagnetic force$ Two!arallel crrentsflowing in the same
direction attract eachother# while two!arallel crrentsflowing in o!!ositedirections re!el each
other$This force leads tothe idea of thenorth and soth!oles of a magnetic
field$
N
S
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(t is !ossi"le to create a magnetic field "y !rodcing an electric crrent# or &ice &ersa$
%hen crrent !asses throgh a coil of wire# itgenerates a magnetic field along the access of the coil$
This is called electromagnetism
crrent
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The Earth itself is a magnet# with a magnetic north
!ole and soth !ole$
S
N The Earth’s magnetic fieldcontinally tra!s mo&ingcharged !articles coming from
the sn# called solar wind$
The origin of the Earth’s magnetic field issaid to "e a reslt of the dynamo effect#
electric crrents !rodced "y the rotationof the iron)nickel core$
High concentrations of these !articles within the field are called the*an Allen +adiation "elts$
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Solar Wind consists of gases comprisedof protons, electrons, and ions which
hurl towards the earth from the sun at
velocities of 45 !m"sec or higher.
#he path of these particles change almost
directly as they hit the earth$s
magnetosphere at the region called the bow
shoc!.
%ecause the charged particles of the rays are
deflected around the magnetosheath,
the earth is protected from most of the deadlyradiation.
Bow ShockMagnetosheath
#he impact of the solar wind causes
#he field lines facing the sun to compress,While the field lines on the other side stream bac! to form a
Magnetotail.
Magnetotail
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Some solar wind !articles# howe&er# do esca!e the earth’s magnetos!here andcontri"te to the *an Allen radiation "elts$
%hen these !articles do enter the magnetic field# they go throgh three motions,
• S!iral) the !article takes a s!iraling motion arond a magnetic field line$
• Bonce) the !articles e&entally "once towards the o!!osite !ole# where theys!iral again$
• -rift) as the !article continally s!irals and "onces# it drift arond the magneticfield and is tra!!ed in the magnetos!here$
(n order to "etter nderstand the motion of !articles throgh a magnetic field#we ha&e condcted an ex!eriment in&ol&ing creating an electron "eam andrnning it throgh magnets as a !arallel to solar wind entering the earth’s
magnetic field$
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.$/ *olts
012 *olts3late is heated andelectrons "oil off$
*elocity4 23otential Energy4 5 m&61
Electrons are attracted to !ositi&ely charged!late$ They accelerate towards it and small
!ercentage esca!e the !late throgh smallhole# creating electron "eam$
The !otential energyof electrons is con&erted
to kinetic energy
Since change in energy is the&oltage times the chargethen 5m&748*Therefore &4 9:18*;m<
9
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We now know that v= 9:18*;m
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%n or&er to 're&ctthe angle at whch
the electrons are
&eflecte& we *st
frst eas*re
the force that the
agnetc fel& nserts
*'on the +ea
"o &o ths we *se the eq*aton#
,=qv
Magnetic field
Electrons
ke /olar Wn&
the electrons n the
" +ea are
&eflecte&
when enterng a
agnetc fel&
therefore the
electron
+ea +en&s.3
"he force s alwa4s
5er'en&c*lar to the agnetc fel&
n& the veloct4 of the electrons
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%n or&er to fn& the force of the agnetc fel& we *st frst calc*late ts strenghth.
ass= 9.11•10^-!1 kg
veloct4= .$=?1•026. m;s
n& we eas*re& the &stance of the electron +ea fro the agnetsto +e .078 eters
"herefore = (?$00•026)/0
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Now that we know the strength of the magnetic field at the electron "eam# we canalclate the force which the field exerts !on the electrons$
'48&B
'4:.=?•026.
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Conclusion
•The earth’s magnetic field and how it shields theearth from solar wind
•How to find the force that magnetic fieldexerts !on charged !articles and the
strength of the field itself$
•The mo&ement of charged !articles sch as solar wind asthey enter a magnetic field
•How to !redict the !ath of a charged !article throgh a
magnetic field
•Basics of Magnetic fields and electromagnetism