Source code for irfpy.earth.bowshock

import os,sys
import math
import logging

import numpy as np

class BsModelFairfield():
	''' Bow shock model proposed by Fairfield et al., 1971 '''

	def __init__(self):
		self.a = 0.0296
		self.b = -0.0381
		self.c = -1.280
		self.d = 45.644
		self.e = -652.10
		self._re = 6378.
	

	def isInside(self, x, y, z):
		''' Return true if the position (x,y,z)[Rm] is in or on the bow shock. '''
		r = math.sqrt(y*y+z*z)
		f = r**2 + self.a*x*r + self.b * (x**2) + self.c * r + self.d * x + self.e
		return f<0

	def isInsideKm(self, x, y, z):
		''' Return true if the position (x,y,z)[Km] is in or on the bow shock. '''
		rx = x/self._re
		ry = y/self._re
		rz = z/self._re
		return self.isInside(rx,ry,rz)

	def getBounds2D(self):
		### x range is x < 14.46
		a,b,c,d,e = self.a,self.b,self.c,self.d,self.e
		arr=[]

		def _solve(x):
			DD = (c+a*x)**2 - 4 * (b*x*x+d*x+e)
			DD = math.sqrt(DD)
			y= (DD - c - a*x)/2
			return y
			
		for x in range(-1000,144):
			x=x/10.
			y=_solve(x)
			arr.append([x,y])
		for x in range(1440,1447):
			x=x/100.
			y=_solve(x)
			arr.append([x,y])

		return arr

def getboundary():
    ''' Return the boundary in Rm.
    '''
    model = BsModelFairfield()
    return model.getBounds2D()

import unittest
import doctest


def doctests():
    return unittest.TestSuite((
        doctest.DocTestSuite(),
        ))
if __name__ == '__main__':
    unittest.main(defaultTest='doctests')