Good Evening,
It was a good week; my to do list could not keep up with me. I think
it was the sun. Mix in a little rain and you get a lot more flowers.
And hummingbirds. The sun also sent more ions. We are currently inside
a stream of solar wind. There was an X class flare a few days ago. The
ionosphere should be ready for us tomorrow. QSB will add interest.
Please join us on (or near):
14050 kHz at 2200z Sunday (3 PM PDT Sunday)
7047 kHz at 0000z Monday (5 PM PDT Sunday)
73,
Kevin. KD5ONS
-
I am modeling the motion of a charged particle through a magnetic field,
by implementing the Lorentz Force equation. Only the magnetic portion
for now, the electric part comes later. Using vectors makes the code
more readable and compact.
This is a rough draft of a streak pattern to display charged particle
motion:
void streak( void )
{
struct spark F; // Force field
float q = 1.6e-19; // Electron charge Ampere*second
float Me = 9.1e-31; // Electron mass in kilograms
struct vt ptC; // Screen point
struct pt Fm; // Magnetic component of Lorentz Force in
Newtons
struct pt Vv = vector( 5e5, 0.0, 0.0 ); // 500 km/second
float dt = 1e-2; // Seconds
F.B = vector( 0.0, 1e-5, 0.0 ); // Vertical 1 Gauss field
Fm = vecMult( vecCrossVec( Vv, F.B ), q ); // Magnetic component
of the Lorentz Force
for(int i=0; i<rcount; i++) // Move the ray across display
{
SelectObject( bkhdc, pn[ ray[ i ].col ] ); // Choose preset
pen color
if(( ray[i].X.x > 100.0 ) && ( ray[i].X.x < 400.0 )) // In the
field
{ // F/m = a
ray[i].X = vecPlusVec( ray[i].X, vecMult( vecDiv( Fm, Me ),
dt*dt ));
Vv = vecPlusVec( Vv, vecMult( vecDiv( Fm, Me ), dt );
}
else
ray[ i ].X = vecPlusVec( ray[ i ].X, Vv ); // Move ray to
the right
if( ray[i].X.x > 500.0 ) ray[i].X.x = -100.0; // Arbitrary
endpoint choices
ptC = perspective( matrixMultiply( Transform, matTvec( Rot,
ray[i].X ), View ) );
Ellipse( bkhdc, ptC.x-1, ptC.y+1, ptC.x+1, ptC.y-1 );
}
SelectObject( bkhdc, hpen ); // Restore
standard black pen
}
When this works I will generalize it to animate charged particles in a
toroidal magnetic field.
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