From 665273f5c2ea01eec107936b311d1111733e0bc5 Mon Sep 17 00:00:00 2001
From: Gamelin Alexis <gamelin@synchrotron-soleil.fr>
Date: Fri, 26 Mar 2021 13:59:23 +0100
Subject: [PATCH] Change beam phasor evolution + phasor init
Add phasor initialization (on the "rf" reference)
Change beam phasor evolution to allow for "beam" or "rf" reference
---
tracking/rf.py | 72 +++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 62 insertions(+), 10 deletions(-)
diff --git a/tracking/rf.py b/tracking/rf.py
index 9ed3b00..dd064e5 100644
--- a/tracking/rf.py
+++ b/tracking/rf.py
@@ -188,7 +188,7 @@ class CavityResonator():
self.valid_bunch_index = np.where(beam.filling_pattern == True)[0]
self.tracking = True
- def track(self, beam):
+ def track(self, beam, ref_frame="beam"):
"""version type mbtrack + formule analytique"""
if self.tracking is False:
@@ -210,7 +210,7 @@ class CavityResonator():
# phasor is given at t=0 synchronous particle of the bunch
# remove part of beam phasor decay to be at the start of the binning
- self.phasor_decay(center[0])
+ self.phasor_decay(center[0], ref_frame=ref_frame)
if index != self.bunch_index:
self.phasor_evol(profile, bin_length, charge_per_mp)
@@ -229,17 +229,43 @@ class CavityResonator():
Vtot = Vgene + Vbeam - charge_per_mp*self.loss_factor*mp_per_bin
energy_change[ind] = Vtot / self.ring.E0
- self.phasor_decay(bin_length)
-
self.beam_phasor -= 2*charge_per_mp*self.loss_factor*mp_per_bin
+ self.phasor_decay(bin_length, ref_frame=ref_frame)
- self.phasor_decay( (self.distance[index] * self.ring.T1) - center[-1])
+ self.phasor_decay( (self.distance[index] * self.ring.T1) - center[-1], ref_frame=ref_frame)
if index == self.bunch_index:
# apply kick
bunch["delta"] += energy_change
+ bunch.energy_change = energy_change
+
+
+ def init_phasor(self, beam):
+ """version type mbtrack + formule analytique"""
+
+ if self.tracking is False:
+ self.init_tracking(beam)
+
+ n_turn = int(self.filling_time/self.ring.T0*5)
- def phasor_decay(self, time):
+ for i in range(n_turn):
+ for j, bunch in enumerate(beam.not_empty):
+
+ index = self.valid_bunch_index[j]
+
+ # get shared bunch profile for current bunch
+ center = beam.mpi.center_all[j]
+ profile = beam.mpi.profile_all[j]
+ bin_length = center[1]-center[0]
+ charge_per_mp = beam.mpi.charge_per_mp_all[j]
+
+ # phasor is given at t=0 synchronous particle of the bunch
+ # remove part of beam phasor decay to be at the start of the binning
+ self.phasor_decay(center[0], ref_frame="rf")
+ self.phasor_evol(profile, bin_length, charge_per_mp, ref_frame="rf")
+ self.phasor_decay( (self.distance[index] * self.ring.T1) - center[-1], ref_frame="rf")
+
+ def phasor_decay(self, time, ref_frame="beam"):
"""
Compute the beam phasor decay during a given time span, assuming that
no particles are crossing the cavity during the time span.
@@ -250,10 +276,14 @@ class CavityResonator():
Time span in [s], can be positive or negative.
"""
+ if ref_frame == "beam":
+ delta = self.wr
+ elif ref_frame == "rf":
+ delta = (self.wr - self.ring.omega1)
self.beam_phasor = self.beam_phasor * np.exp((-1/self.filling_time +
- 1j*2*np.pi*self.detune)*time)
+ 1j*delta)*time)
- def phasor_evol(self, profile, bin_length, charge_per_mp):
+ def phasor_evol(self, profile, bin_length, charge_per_mp, ref_frame="beam"):
"""
Compute the beam phasor evolution during the crossing of a bunch.
@@ -266,15 +296,20 @@ class CavityResonator():
charge_per_mp : float
Charge per macro-particle in [C].
"""
+ if ref_frame == "beam":
+ delta = self.wr
+ elif ref_frame == "rf":
+ delta = (self.wr - self.ring.omega1)
+
n_bin = len(profile)
# Phasor decay during crossing time
deltaT = n_bin*bin_length
- self.phasor_decay(deltaT)
+ self.phasor_decay(deltaT, ref_frame)
# Phasor evolution due to induced voltage by marco-particles
k = np.arange(1, n_bin + 1)
- var = np.exp( (-1/self.filling_time + 1j*2*np.pi*self.detune) *
+ var = np.exp( (-1/self.filling_time + 1j*delta) *
(n_bin-k) * deltaT )
sum_tot = np.sum(profile * var)
sum_val = -2 * sum_tot * charge_per_mp * self.loss_factor
@@ -297,11 +332,28 @@ class CavityResonator():
"""Cavity total voltage in [V]"""
return np.abs(self.cavity_phasor)
+ def cavity_real_voltage(self, t):
+ """Cavity total voltage in [V]"""
+ Vg = self.Vg*np.exp(1j*(self.m*self.ring.omega1*t + self.theta_g))
+ Vb = self.beam_phasor*np.exp((-1/self.filling_time +
+ 1j*2*np.pi*self.detune)*t)
+ return np.real(Vg+Vb)
+
@property
def cavity_phase(self):
"""Cavity total phase in [rad]"""
return np.angle(self.cavity_phasor)
+ @property
+ def beam_voltage(self):
+ """Beam loading voltage in [V]"""
+ return np.abs(self.beam_phasor)
+
+ @property
+ def beam_phase(self):
+ """Beam loading phase in [rad]"""
+ return np.angle(self.beam_phasor)
+
@property
def loss_factor(self):
"""Cavity loss factor in [V/C]"""
--
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