# This is a disk dynamo simulation of the earth's magnetic field.
# It attempts to simulate the dramatic switch in the polarity
# of the field that takes place every eon or so.
#
# Source: Michael Steele, B.A. thesis, Reed College, 1981 (Physics)

# You may run this example by doing:
#
#    ode < dynamo.ode | graph -T X -C
#
# or alternatively, to get a real-time plot,
#
#    ode < dynamo.ode | graph -T X -C -x 0 10 -y -10 10
#

# The equations are: 
#
# w' = Q -zy - Vw
# y' = S( Az - y)
# z' = wy - z
# S = 5
# V = 1
# Q = 14.625
# A = 1

A = 1
V = 1
Q = 14.625
S = 5

w' = Q - z * y - V * w
y' = S * ( A * z - y)
z' = w * y - z

w = 1
y = 1
z = 1

print t, z
step 0, 10, .01