def __init__(self, pos=None, vel=None, t0=0, mass=None, charge=None, field=None):
"""
Object constructor.
Parameters
----------
pos: list or array
The initial position (x,y,z) of the particle, in meters.
vel: list or array
The initial velocity (vx, vy, vz) of the particle, in m/s.
t0: float
The time of simulation at the beginning (seconds), ignored for fields that do not depend on time.
mass: float
The mass of the particle, in kg.
charge: float
The charge of the particle, in Coulombs.
field: Field object
The field object that provides electric and magnetic field vectors and related quantities.
"""
self.pos = np.array(pos) # initial position array
self.vel = np.array(vel) # initial velocity array
self.tcur = t0 # current time
self.mass = mass # mass of the particle
self.charge = charge # charge of the particle
self.field = field # the field object
self.p = Particle(pos,vel,t0,mass,charge,field) # Store for referencing in setpa and setKE
self.p.check_adiabaticity = True
if self.p.isadiabatic():
g = GuidingCenter()
g.check_adiabaticity = True
g.init(self.p)
self.trajlist = [g]
else:
self.trajlist = [self.p]
def advance(self,delta):
"""
Advance the tracer position and the relevant momentum for a given duration.
The trajectory is initialized at the latest state of the current tracer
and integrated for an additional `delta` seconds. Uses the settings
specific to the current tracer.
This method can be called many times.
Parameters
----------
delta : float
The number of seconds to advance the trajectory.
"""
t = 0
current = self.trajlist[-1]
assert current.check_adiabaticity == True
while t < delta:
try:
current.advance(delta-t)
except NonAdiabatic:
p = Particle()
p.init(current)
p.check_adiabaticity = True
self.trajlist.append(p)
current = self.trajlist[-1]
print("Switched to particle mode at time", current.tcur,flush=True)
except Adiabatic:
g = GuidingCenter()
g.init(current)
g.check_adiabaticity = True
self.trajlist.append(g)
current = self.trajlist[-1]
print("Switched to guiding center mode at time", current.tcur,flush=True)
t = current.tcur