def ion_dist_single(probe,
year,
doy,
hour,
minute,
second,
remove_advect=False):
"""
Read in ion distribution function.
Parameters
----------
probe : int, string
Helios probe to import data from. Must be 1 or 2.
year : int
Year
doy : int
Day of year
hour : int
Hour
minute : int
Minute.
second : int
Second
remove_advect : bool, optional
If *False*, the distribution is returned in
the spacecraft frame.
If *True*, the distribution is
returned in the solar wind frame, by subtracting the spacecraft
velocity from the velcoity of each bin. Note this significantly
slows down reading in the distribution.
Returns
-------
dist : DataFrame
3D ion distribution function
"""
probe = _check_probe(probe)
f, filename = _loaddistfile(probe, year, doy, hour, minute, second)
nionlines = None # Number of lines in ion distribution
linesread = 0 # Stores the total number of lines read in the file
# Loop through file to find end of ion distribution function
for i, line in enumerate(f):
# Find start of proton distribution function
if line[0:23] == 'Maximum of distribution':
ionstartline = i + 1
# Find number of lines in ion distribution function
if line[0:4] == ' 2-D':
nionlines = i - ionstartline
break
linesread += i
# Bizzare case where there are two proton distributions in one file,
# or there's no electron data available
for i, line in enumerate(f):
if line[0:23] == 'Maximum of distribution' or\
line[0:30] == ' 1.2 Degree, Pizzo correction' or\
line[0:30] == ' -1.2 Degree, Pizzo correction':
warnings.warn("More than one ion distribution function found",
RuntimeWarning)
# NOTE: Bodge
linesread -= 1
break
f.close()
# If there's no electron data to get number of lines, set end of ion
# distribution function to end of file
if nionlines is None:
nionlines = i - ionstartline + 1
#####################################
# Read and process ion distribution #
#####################################
# If no ion data in file
if nionlines < 1:
raise RuntimeError('No ion distribution function data in file')
# Arguments for reading in data
readargs = {
'usecols': [0, 1, 2, 3, 4, 5, 6, 7],
'names': ['Az', 'El', 'E_bin', 'pdf', 'counts', 'vx', 'vy', 'vz'],
'delim_whitespace': True,
'skiprows': ionstartline,
'nrows': nionlines
}
# Read in data
dist = pd.read_table(filename, **readargs)
# Remove spacecraft abberation
# Assumes that spacecraft motion is always in the ecliptic (x-y)
# plane
if remove_advect:
params = distparams_single(probe, year, doy, hour, minute, second)
dist['vx'] += params['helios_vr']
dist['vy'] += params['helios_v']
# Convert to SI units
dist[['vx', 'vy', 'vz']] *= 1e3
dist['pdf'] *= 1e12
# Calculate magnitude, elevation and azimuth of energy bins
dist['|v|'], dist['theta'], dist['phi'] =\
util._cart2sph(dist['vx'], dist['vy'], dist['vz'])
# Calculate bin energy assuming particles are protons
dist['E_proton'] = 0.5 * constants.m_p.value * ((dist['|v|'])**2)
# Convert to multi-index using azimuth, elevation, and energy bins
dist = dist.set_index(['E_bin', 'El', 'Az'])
return dist
def electron_dist_single(probe,
year,
doy,
hour,
minute,
second,
remove_advect=False):
"""
Read in 2D electron distribution function.
Parameters
----------
probe : int, string
Helios probe to import data from. Must be 1 or 2.
year : int
Year
doy : int
Day of year
hour : int
Hour.
minute : int
Minute
second : int
Second
remove_advect : bool, optional
If ``False``, the distribution is returned in
the spacecraft frame.
If ``True``, the distribution is
returned in the solar wind frame, by subtracting the spacecraft
velocity from the velcoity of each bin. Note this significantly
slows down reading in the distribution.
Returns
-------
dist : DataFrame
2D electron distribution function
"""
probe = _check_probe(probe)
f, filename = _loaddistfile(probe, year, doy, hour, minute, second)
startline = None
for i, line in enumerate(f):
# Find start of electron distribution function
if line[0:4] == ' 2-D':
startline = i + 2
# Throw away next line (just has max of distribution)
f.readline()
# Throw away next line (just has table headings)
if f.readline()[0:27] == ' no electron data available':
return None
break
nlines = None
for i, line in enumerate(f):
if 'Degree, Pizzo correction' in line:
break
nlines = i + 1
if startline is None:
return None
##########################################
# Read and process electron distribution #
##########################################
# Arguments for reading in data
readargs = {
'usecols': [0, 1, 2, 3, 4, 5],
'names': ['Az', 'E_bin', 'pdf', 'counts', 'vx', 'vy'],
'delim_whitespace': True,
'skiprows': startline,
'nrows': nlines
}
# Read in data
dist = pd.read_table(filename, **readargs)
if dist.empty:
return None
# Remove spacecraft abberation
# Assumes that spacecraft motion is always in the ecliptic (x-y)
# plane
if remove_advect:
params = distparams_single(probe, year, doy, hour, minute, second)
dist['vx'] += params['helios_vr']
dist['vy'] += params['helios_v']
# Convert to SI units
dist[['vx', 'vy']] *= 1e3
dist['pdf'] *= 1e12
# Calculate spherical coordinates of energy bins
dist['|v|'], _, dist['phi'] =\
util._cart2sph(dist['vx'], dist['vy'], 0)
# Calculate bin energy assuming particles are electrons
dist['E_electron'] = 0.5 * constants.m_e.value *\
((dist['|v|']) ** 2)
# Convert to multi-index using Azimuth and energy bin
dist = dist.set_index(['E_bin', 'Az'])
f.close()
return dist
