def setke(self, ke, unit="ev"):
"""
Scale the velocity vector with the speed corresponding to the given kinetic energy.
Reinitializes the object.
Parameters
-----------
ke : float
The kinetic energy of the particle (eV by default). Can be relativistic.
unit : str, optional
The unit of the energy. If "ev", electron volts, otherwise Joule.
"""
# Calculate the current pitch angle
mc = self.mass*c
t,x,y,z,ppar = self.trajectory[-1]
B = self.field.magB(self.trajectory[-1,:4])
gammasq_minus_1 = 2*self.mu*B/(mc*c) + (ppar/mc)**2
if np.sqrt(gammasq_minus_1 + 1) - 1 < 1e-6: # nonrelativistic
ptot = np.sqrt(2*self.mass*self.mu*B + ppar**2) # total momentum
else: # relativistic
ptot = np.sqrt(gammasq_minus_1)*mc # total momentum
pa_old = np.arccos(ppar/ptot)
# Find the new speed corresponding to the given relativistic energy
v_new = ru.speedfromKE(ke, self.mass, unit) # new speed
# Reinitialize the guiding center
self.__init__(pos=[x,y,z], v=v_new, pa=pa_old, t0=t,
mass=self.mass, charge=self.charge, field=self.field )
def setke(self, ke, unit="ev"):
"""
Scale the velocity vector with the speed corresponding to the given kinetic energy.
Reinitializes the object.
Parameters
-----------
ke : float
The kinetic energy of the particle (eV by default). Can be relativistic.
unit : str, optional
The unit of the energy. If "ev", electron volts, otherwise Joule.
"""
# Calculate the current pitch angle
mc = self.mass*c
t,x,y,z,ppar = self.trajectory[-1]
B = self.field.magB(self.trajectory[-1,:4])
gammasq_minus_1 = 2*self.mu*B/(mc*c) + (ppar/mc)**2
if np.sqrt(gammasq_minus_1 + 1) - 1 < 1e-6: # nonrelativistic
ptot = np.sqrt(2*self.mass*self.mu*B + ppar**2) # total momentum
else: # relativistic
ptot = np.sqrt(gammasq_minus_1)*mc # total momentum
pa_old = np.arccos(ppar/ptot)
# Find the new speed corresponding to the given relativistic energy
v_new = ru.speedfromKE(ke, self.mass, unit) # new speed
# Reinitialize the guiding center
self.__init__(pos=[x,y,z], v=v_new, pa=pa_old, t0=t,
mass=self.mass, charge=self.charge, field=self.field )
def setke(self,ke, unit="ev"):
"""
Scale the velocity vector with the speed corresponding to the given kinetic energy.
Reinitializes the object.
Parameters
-----------
ke : float
The kinetic energy of the particle (eV by default). Can be relativistic.
unit : str, optional
The unit of the energy. If "ev", electron volts, otherwise Joule.
"""
assert ke > 0
s = ru.speedfromKE(ke, self.mass, unit)
mom = self.trajectory[-1,4:]
gm = np.sqrt(self.mass**2 + np.dot(mom,mom)/c**2) # gamma * m
v = mom/gm # velocity
v = v*(s/np.sqrt(np.dot(v,v)))
self.__init__(self.pos, v, self.t0, self.mass, self.charge, self.field)
def setke(self, ke, unit="ev"):
"""
Scale the velocity vector with the speed corresponding to the given kinetic energy.
Reinitializes the object.
Parameters
-----------
ke : float
The kinetic energy of the particle (eV by default). Can be relativistic.
unit : str, optional
The unit of the energy. If "ev", electron volts, otherwise Joule.
"""
assert ke > 0
s = ru.speedfromKE(ke, self.mass, unit)
mom = self.trajectory[-1, 4:]
gm = np.sqrt(self.mass**2 + np.dot(mom, mom) / c**2) # gamma * m
v = mom / gm # velocity
v = v * (s / np.sqrt(np.dot(v, v)))
self.__init__(self.pos, v, self.t0, self.mass, self.charge, self.field)
