Modeling an Arcade of Loops with the RTV Scaling Laws

This example shows how to model AIA emission from an arcade of semi-circular loops who’s thermal structure is modeled using the RTV scaling laws.

import astropy.time
import astropy.units as u

from astropy.coordinates import SkyCoord
from sunpy.coordinates import get_earth

import synthesizAR

from synthesizAR.instruments.sdo import InstrumentSDOAIA
from synthesizAR.interfaces import RTVInterface
from synthesizAR.models import semi_circular_arcade

First, set up the coordinates for loops in the arcade.

obstime = astropy.time.Time('2022-11-14T22:00:00')
pos = SkyCoord(lon=15*u.deg, lat=25*u.deg, radius=1*u.AU, obstime=obstime, frame='heliographic_stonyhurst')
arcade_coords = semi_circular_arcade(80*u.Mm, 5*u.deg, 50, pos, inclination=10*u.deg)

Next, assemble the arcade.

strands = [synthesizAR.Strand(f'strand{i}', c) for i, c in enumerate(arcade_coords)]
arcade = synthesizAR.Skeleton(strands)

We can make a quick plot of what these coordinates would look like as viewed from Earth.

earth_observer = get_earth(obstime)
arcade.peek(observer=earth_observer,
            axes_limits=[(150, 300)*u.arcsec, (275, 425)*u.arcsec])

Next, model the thermal structure of each loop using the RTV scaling laws.

rtv = RTVInterface(heating_rate=1e-6*u.Unit('erg cm-3 s-1'))
arcade.load_loop_simulations(rtv)

Finally, compute the LOS integrated AIA emission.

aia = InstrumentSDOAIA([0, 1]*u.s, earth_observer, pad_fov=(40, 40)*u.pixel)
maps = aia.observe(arcade)

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INFO: Apparent body location accounts for 493.67 seconds of light travel time [sunpy.coordinates.ephemeris]

We can make a quick plot of what each EUV channel of AIA would look like.

for k in maps:
    maps[k][0].peek()

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We can easily adjust the viewing angle to integrate the emission along a different LOS.

off_limb_observer = SkyCoord(
    lon=-70*u.deg, lat=earth_observer.lat, radius=earth_observer.radius, frame=earth_observer.frame)
aia = InstrumentSDOAIA([0, 1]*u.s, off_limb_observer, pad_fov=(20, 20)*u.pixel,)
maps = aia.observe(arcade)
for k in maps:
    maps[k][0].peek(draw_limb=True)

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INFO: Apparent body location accounts for 493.67 seconds of light travel time [sunpy.coordinates.ephemeris]