Discontinuous Galerkin Library
#include "dg/algorithm.h"

\(f(R,Z) = A B \sum_\vec{k} \sqrt{E_k} \alpha_k \cos{\left(k \kappa_k + \theta_k \right)} \) More...

Public Member Functions

 BathRZ (unsigned N_kR, unsigned N_kZ, double R_min, double Z_min, double gamma, double L_E, double amp)
 Functor returning a random field in the RZ-plane or in the first RZ-plane. More...
 
double operator() (double R, double Z) const
 Return the value of the Bath. More...
 
double operator() (double R, double Z, double phi) const
 Return the value of the Bath. More...
 

Detailed Description

\(f(R,Z) = A B \sum_\vec{k} \sqrt{E_k} \alpha_k \cos{\left(k \kappa_k + \theta_k \right)} \)

A random bath in the R-Z plane with

\[ B := \sqrt{\frac{2}{N_{k_R} N_{k_Z}}} \\ k:=\sqrt{k_R^2 + k_Z^2} \\ k_R:=2 \pi \left( i -N_{k_R}/2\right)/N_{k_R} \\ k_Z:=2 \pi \left( j -N_{k_Z}/2\right)/N_{k_Z} \\ k_0:=2 \pi L_E / N_k\\ N_k := \sqrt{N_{k_R}^2 + N_{k_Z}^2} \\ E_k:=\left(4 k k_0/(k+k_0)^2\right)^{\gamma} \\ \alpha_k := \sqrt{\mathcal{N}_1^2 + \mathcal{N}_2^2} \\ \theta_k := \arctan{\left(\mathcal{N}_2/\mathcal{N}_1\right)} \\ \kappa_k(R,Z) := (R-R_{min}) \mathcal{U}_1 + (Z-Z_{min}) \mathcal{U}_2 \\ \]

where \(\mathcal{N}_{1,2}\) are random normal distributed real numbers with a mean of \(\mu = 0\) and a standard deviation of \(\sigma=1 \), \(\mathcal{U}_{1,2}\) are random uniformly distributed real numbers \(\in \left[0, 2 \pi \right) \) and \( A \) is the amplitude.

Constructor & Destructor Documentation

◆ BathRZ()

dg::BathRZ::BathRZ ( unsigned  N_kR,
unsigned  N_kZ,
double  R_min,
double  Z_min,
double  gamma,
double  L_E,
double  amp 
)
inline

Functor returning a random field in the RZ-plane or in the first RZ-plane.

Parameters
N_kRNumber of Fourier modes in R direction
N_kZNumber of Fourier modes in Z direction
R_minMinimal R (in units of rho_s)
Z_minMinimal Z (in units of rho_s)
gammaexponent in the energy function \(E_k\) (typically around 30)
L_Eis the typical eddysize (typically around 5)
ampAmplitude

Member Function Documentation

◆ operator()() [1/2]

double dg::BathRZ::operator() ( double  R,
double  Z 
) const
inline

Return the value of the Bath.

\[f(R,Z) = A B \sum_\vec{k} \sqrt{E_k} \alpha_k \cos{\left(k \kappa_k + \theta_k \right)} \]

with

\[ \mathcal{N} := \sqrt{\frac{2}{N_{k_R} N_{k_Z}}} \\ k:=\sqrt{k_R^2 + k_Z^2} \\ k_R:=2 \pi \left( i -N_{k_R}/2\right)/N_{k_R} \\ k_Z:=2 \pi \left( j -N_{k_Z}/2\right)/N_{k_Z} \\ k_0:=2 \pi L_E / N_k\\ N_k := \sqrt{N_{k_R}^2 + N_{k_Z}^2} \\ E_k:=\left(4 k k_0/(k+k_0)^2\right)^{\gamma} \\ \alpha_k := \sqrt{\mathcal{N}_1^2 + \mathcal{N}_2^2} \\ \theta_k := \arctan{\left(\mathcal{N}_2/\mathcal{N}_1\right)} \\ \kappa_k(R,Z) := (R-R_{min}) \mathcal{U}_1 + (Z-Z_{min}) \mathcal{U}_2 \\ \]

where \(\mathcal{N}_{1,2}\) are random normal distributed real numbers with a mean of \(\mu = 0\) and a standard deviation of \(\sigma=1 \), \(\mathcal{U}_{1,2}\) are random uniformly distributed real numbers \(\in \left[0, 2 \pi \right) \) and \( A \) is the amplitude

Parameters
RR - coordinate
ZZ - coordinate
Returns
the above function value

◆ operator()() [2/2]

double dg::BathRZ::operator() ( double  R,
double  Z,
double  phi 
) const
inline

Return the value of the Bath.

\[f(R,Z) = A B \sum_\vec{k} \sqrt{E_k} \alpha_k \cos{\left(k \kappa_k + \theta_k \right)} \]

with

\[ \mathcal{N} := \sqrt{\frac{2}{N_{k_R} N_{k_Z}}} \\ k:=\sqrt{k_R^2 + k_Z^2} \\ k_R:=2 \pi \left( i -N_{k_R}/2\right)/N_{k_R} \\ k_Z:=2 \pi \left( j -N_{k_Z}/2\right)/N_{k_Z} \\ k_0:=2 \pi L_E / N_k\\ N_k := \sqrt{N_{k_R}^2 + N_{k_Z}^2} \\ E_k:=\left(4 k k_0/(k+k_0)^2\right)^{\gamma} \\ \alpha_k := \sqrt{\mathcal{N}_1^2 + \mathcal{N}_2^2} \\ \theta_k := \arctan{\left(\mathcal{N}_2/\mathcal{N}_1\right)} \\ \kappa_k(R,Z) := (R-R_{min}) \mathcal{U}_1 + (Z-Z_{min}) \mathcal{U}_2 \\ \]

where \(\mathcal{N}_{1,2}\) are random normal distributed real numbers with a mean of \(\mu = 0\) and a standard deviation of \(\sigma=1 \), \(\mathcal{U}_{1,2}\) are random uniformly distributed real numbers \(\in \left[0, 2 \pi \right) \) and \( A \) is the amplitude

Parameters
RR - coordinate
ZZ - coordinate
phiphi - coordinate
Returns
the above function value

The documentation for this struct was generated from the following file: