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DiMPl - Dust In Magnetised Plasma

Simulates trajectories of ions and electrons in a magnetised plasma around a charged dust grain.
Rate of collection of ions and electrons is calculated with a focus on calculating the torque on the sphere.

A more detailed description of the methodology of DiMPl and results for charging in a magnetic field are provided in the follow paper:

L. Simons and M. Coppins, Phys. Plasmas 27, 063702 (2020). DOI: https://doi.org/10.1063/5.0005392

A detailed look at the dependence of the forces experienced by dust grains in magnetic fields in flowing plasmas is provided in the following paper:

L. James and M. Coppins, Phys. Plasmas (2020).


This code calculates the angular and linear momentum transfer to a charged sphere with either a Debye-Huckel or Coulomb electric potential in a constant magnetic field. Output is in files in subdirectory Data. Optional full tracking of particles, including their change in energy and net linear and angular momentum can be calculated by defining the relevant pre-processor directives. Command line input is available with the following options:

Options:
	-h,--help			Show this help message

	-r,--radius RADIUS		(m), Specify radius of Dust grain
		Radius(=1e-6m) DEFAULT,		By Default, simulate sphere of size 1um in radius

	-s,--spin SPIN		(hz), Specify the initial rotation frequency of Dust grain alligned with magnetic field axis
		Spin(=0.0hz) DEFAULT,		By Default, simulate sphere with initially zero z angular momentum

	-a1,--semix SEMIX		(arb), Specify the semi-axis for x in dust radii
		a1(=1) DEFAULT,			By Default, simulate perfect sphere

	-a2,--semiy SEMIY		(arb), Specify the semi-axis for y in dust radii
		a2(=1) DEFAULT,			By Default, simulate perfect sphere

	-a3,--semiz SEMIZ		(arb), Specify the semi-axis for z in dust radii
		a3(=1) DEFAULT,			By Default, simulate perfect sphere

	-d,--density DENSITY		(kgm^-^3), Specify density of Dust grain
		Density(=19600kgm^-^3) DEFAULT,	By Default, Tungsten Density

	-ex,--efieldx EFIELDX	(double), Specify the x component of a background electric field
	-ey,--efieldx EFIELDY	(double), Specify the y component of a background electric field
	-ez,--efieldx EFIELDZ	(double), Specify the z component of a background electric field

	-p,--potential POTENTIAL	(double), Specify the potential of Dust grain normalised to electron temperature
		Potential(=-2.5eV) DEFAULT,	By Default, OML Potential in Ti=Te Hydrogen plasma

	-m,--magfield MAGFIELD		(T), Specify the magnetic field (z direction)
		BMag(=1.0T) DEFAULT,		By Default, magnetic field is 1.0T upwards in vertical z

	-n,--normalised NORMALISED	(bool), whether normalisation (following Sonmor & Laframboise) is on or off
		NormVars(=0) DEFAULT,	False, By Default use Tesla and electron volts

	-te,--etemp ETEMP		(eV), Specify the temperature of plasma electrons
		eTemp(=1eV) DEFAULT,

	-ne,--edensity EDENSITY		(m^-^3), Specify the plasma electron density
		eDensity(=1e18m^-^3) DEFAULT,	Tokamak density

	-mi,--imass IMASS		(u), Specify the mass of Ions in Daltons
		iMass(=1u) DEFAULT,

	-ti,--itemp ITEMP		(eV), Specify the temperature of Ions
		iTemp(=1eV) DEFAULT,

	-ni,--idensity IDENSITY		(m^-^3), Specify the plasma ion density
		iDensity(=1e18m^-^3) DEFAULT,	Tokamak density

	-c,--ichance ICHANCE			(eV), Specify the probability of generating an Ion
		iChance(=-0.5) DEFAULT,	Ficticious ion generation probability: i.e Self-consistently generate ions & electrons

	-u,--zmaxcoeff ZMAXCOEFF	(double), The upper limit of simulation domain as number of Coulomb Interaction lengths
		zMaxCoeff(=1.0) DEFAULT,	Distance from (0,0,Radius) plane to max of simulation domain in dust radii

	-l,--zmincoeff ZMINCOEFF	(double), The lower limit of simulation domain as number of Coulomb Interaction lengths
		zMaxCoeff(=1.0) DEFAULT,	Distance from (0,0,Radius) plane to min of simulation domain in dust radii

	-z,--zboundforce ZBOUNDFORCE	(double), Force the absolute value of simulation domain upper and lower boundaries
		ZBoundForce(=0.0) DEFAULT,	By Default, use -u and -l to determine height of injection plane

	-b,--impactpar IMPACTPAR	(double), Specify the radial limit of simulation domain as multiple of gyro-radii and debye lengths
		ImpactPar(=2.0) DEFAULT,	By Default, Radial extent of injection is two gyro-radii plus two debye lengths from dust

	-f,--forceimppar FORCEIMPPAR	(double), Force the absolute value of simulation radial distance
		ForceImpPar(=0.0) DEFAULT,	By Default, use -b to determine radial extent of injection plane

	-i,--imax IMAX			(int), Specify the number of particles to be launched
		imax(=10000) DEFAULT,		By Default, inject 10,000 particles

	-j,--jmax JMAX			(int), Specify the number of particles to be collected (not exceeding imax)
		jmax(=5000) DEFAULT,		By Default, stop simulation if 5,000 particles are collected

	-rm,--rmax RMAX			(int), Specify the number of reflections in z axis before assuming orbit misses
		rmax(=15) DEFAULT,		By Default, stop simulation if Particle reflects in z axis 15 times

	-t,--timestep TIMESTEP		(double), Specify the multiplicative factor for the time step
		TimeStepFactor(=0.0005) DEFAULT,

	-no,--number NUMBER			(int), Specify the number of particles to be captured before saving
		Number(=1000) DEFAULT,		By Default, store average values after collecting 1000 particles

	-v,--driftvel DRIFTVEL		(m s^-^1), Specify the drift velocity of the plasma
		DriftVel(=0.0) DEFAULT,		By Default, No drift velocity

	-se,--seed SEED			(double), Specify the seed for the random number generator
		Seed(=1.0) DEFAULT,		By Default, Seed is 1.0

	-sa,--saves SAVES			(int), Specify the number of particles before saving a run
		Saves(=1000) DEFAULT,		By Default, Save data to Meta datafile once per 1000.0 particles

	-o,--output OUTPUT		(string), Specify the suffix of the output file
		suffix(='.txt') DEFAULT,	By Default, Save data to Data/DiMPl.txt




Additional Options from VARIABLE_CSCALE!
	-cs,--chargescale CHARGESCALE			((double), Specify the scale of the charging
		ChargeScale(=0) DEFAULT,		By Default, charging scale is calculated from Potential~1




Additional Options from VARIABLE_CSCALE OR VARIABLE_ASCALE!
	-jm,--jmin JMIN			(int), Specify the number of particles to be collected before dynamic saving
		jmin(=20) DEFAULT,		By Default, re-assess dynamic scale after collecting 20 particles

	-jf,--jfin JMIN			(int), Specify the number of particles to be collected in final save
		jfin(=100) DEFAULT,		By Default, collect 100 particles in the final save



Additional Options from CUSTOM_POTENTIAL
    -cf, --customfield CUSTOMFIELD			(string), Specify the Custom Field file name to be used
        custom electric potential file name(='Custom_Fields/Default_Field.txt') DEFAULT, 	By Default, Load file Custom_Fields/Default_Field.txt