1. NUMERICAL CODES
Frank Lanfa Wang
by

2. 2D parabolic solver for Impedance calculation
 L. Wang, L. Lee, G. Stupakov, fast 2D solver
(IPAC10)
0 200 400 600 800 1000
-0.01
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
f (GHz)
ReZ,ImZ(k)
Real, ECHO2
Imaginary, ECHO2
Real, FEM code
Imaginary, FEM code
0 10 20 30 40 50 60
0
0.5
1
1.5
2
2.5
z (mm)
r(mm)
0 200 400 600 800 1000
-0.02
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
f (GHz)
ReZ,ImZ(k)
Real, ECHO2
-Imaginary, ECHO2
dot-lines: FEM code
0 2 4 6 8 10
0
0.1
0.2
0.3
0.4
0.5
z (cm)
r(cm)
Echo2, sigl=0.1mm

3. Impedance of
Grooved surface
Adaptive method
Speedup and improve accuracy
Mesh of chamber & beam
•Arbitrary geometry of beam pipe
•Any shape of beam

4. FEM CSR code
4
0
0
2
2 ~
2
2
n
e
s
ki
R
xk
 

















E 0
0
2 1


  b
E

5. FEM 2D RF structure
5

6. Real charge distribution Meshed Charge distribution
6 11/10/2016
3D PIC Program--- CLOUDLAND --3D space charge
Program model
Various magnetic field
(dipole…)
& Electric field (clearing
electrode, …)
PIC methods
2h
l
L
x
y
z
p
+ e- 2a
CLOUDLAND is a complete 3D PIC code (PRST-AB 124402)
Charge assignment
Mesh of
chamber

7. 7
A THz source by up-converting rf with plasma waveguide
rp
Hollow Plasma
rc
RF cavity
Virtual plasma cavity
0 2 4 6 8 10 12
0
0.2
0.4
0.6
0.8
1
f (THz)
Spectrumofelectricenergy(a.u.)
=500
=5000
=50000
=500000
0 0.2 0.4 0.6 0.8 1
10
-3
10
-2
10
-1
10
0
10
1
Time (T0
)
Electricenergy
/=7.5
/=3.8
/=1.5
/=0.75
/=0.45
Appl. Phys. Lett.105, 183502 (2014);