import logging
import numpy as np
from pytplot import get_data, store_data
from geopack import geopack, t89
[docs]
def tt89(pos_var_gsm, iopt=3, suffix='', igrf_only=False):
"""
tplot wrapper for the functional interface to Sheng Tian's implementation
of the Tsyganenko 96 and IGRF model:
https://github.com/tsssss/geopack
Input
------
pos_gsm_tvar: str
tplot variable containing the position data (km) in GSM coordinates
Parameters
-----------
iopt: int
Specifies the ground disturbance level:
========= ======== ======= ======= ======= ======= =======
iopt= 1 2 3 4 5 6 7
kp= 0,0+ 1-,1,1+ 2-,2,2+ 3-,3,3+ 4-,4,4+ 5-,5,5+ > =6-
========= ======== ======= ======= ======= ======= =======
suffix: str
Suffix to append to the tplot output variable
Returns
--------
Name of the tplot variable containing the model data
"""
pos_data = get_data(pos_var_gsm)
if pos_data is None:
logging.error('Variable not found: ' + pos_var_gsm)
return
b0gsm = np.zeros((len(pos_data.times), 3))
dbgsm = np.zeros((len(pos_data.times), 3))
# convert to Re
pos_re = pos_data.y/6371.2
for idx, time in enumerate(pos_data.times):
tilt = geopack.recalc(time)
# IGRF B in GSM
b0gsm[idx, 0], b0gsm[idx, 1], b0gsm[idx, 2] = geopack.igrf_gsm(pos_re[idx, 0], pos_re[idx, 1], pos_re[idx, 2])
# T89 dB in GSM
dbgsm[idx, 0], dbgsm[idx, 1], dbgsm[idx, 2] = t89.t89(iopt, tilt, pos_re[idx, 0], pos_re[idx, 1], pos_re[idx, 2])
if igrf_only:
bgsm = b0gsm
else:
bgsm = b0gsm + dbgsm
saved = store_data(pos_var_gsm + '_bt89' + suffix, data={'x': pos_data.times, 'y': bgsm})
if saved:
return pos_var_gsm + '_bt89' + suffix