1. DKIST Coronal Spectroscopy: The Missing Link in Coupling
SHINE 2017 Session 8
DKIST Coronal Spectroscopy:
The Missing Link in Coupling
the Sun and Heliosphere
Progress & Prospects Report
Organizers:
Steve Cranmer (CU Boulder)
Mari Paz Miralles (SAO)
Valentín Martínez Pillet (NSO)
Scott McIntosh (HAO)

2. Session 8 Goals & Questions
In order to test/validate theoretical models, we need comprehensive measurements of plasma in the “gap” between disk-imagers & outer-field coronagraphs.
Upcoming programs (e.g., DKIST) will employ new combinations of inner-field coronagraphy & spectroscopy. Here we explore what they’ll do and how they’ll help us answer long-standing questions.
Do we understand the data analysis challenges in converting measurements into useful constraints on models/theory?
What computational tools are needed to make best use of the coming flood of data?
Do we understand the atomic physics effects well enough to be able to improve 3D coronal magnetic field measurements?
What are the tradeoffs between global coronagraphs (e.g., CoMP, COSMO) and small field-of-view, high-throughput instruments (Cryo-NIRSP on DKIST) ?
To what extent can “new” off-limb emission lines be used to better probe physics?

3. Schedule
2:00 – 3:15:
Brief introduction from session organizers (this!)
Scene-setting talk #1: Laurel Rachmeler, NASA/MSFC: “Challenges in Spectro-polarimetric Measurements of the Coronal and Chromospheric Magnetic Field”

4. Remote sensing the invisible
How do we remotely measure something that doesn’t emit light? The magnetic field is invisible, but it does affect the plasma it is embedded in and the light that is emitted and scattered by that plasma.
- public domain image

5. Observations of solar B. Bits and pieces of the puzzle everywhere
EUV/XRay
magnetic morphology
bright flux tubes only
Coronagraph WL
plasma density
only above the limb
Hanle effect
B⃑, or only direction
only direction if saturated
Zeeman effect
|BLOS|,|BPOS|, 𝜽POS
very weak in the corona
Gyroresonance
|B|
only in strong-field regions (now)
Bremsstrahlung
|BLOS|
in a single solar layer
coronal seismology
|B|, 𝜽POS direction
depends on assumed wave mode
Faraday rotation
limited LOSes available
flaring radio emission
Type II, III, etc
intermittent in time
no one technique has all the information. but they all sample slightly different plasma, even at the same location, so we have to be careful about combining.
each technique has its own drawback either limited info/limited sampling/weak signal/etc.
Forward modelling lets you see what information each technique would provide and give a work-space for combining this information in various ways. obviously there are still assumptions that are made, about the other plasma parameters (density, temp, filling factor, etc) and about the methods (i.e. the physics behind the emission/scattering/level populations/etc.
tried to put the most well-known in here, but its not an exhaustive list
many will be used in this session’s talks and posters. You will hear about FORWARD, and IDL set of codes that does create the synthetic obs data for several of these observations.
laser plasmas in the lab, laser corona studies.
flaring radio emission - type 1,2,3, bursts, generally associated with CMEs
scintillation is mostly for density, for cmes
doppler: pos B strength
craig’s method? with heliospheric imagers?

6. Observations of solar B. Bits and pieces of the puzzle everywhere
EUV/XRay
magnetic morphology
bright flux tubes only
Coronagraph WL
plasma density
only above the limb
Hanle effect
B⃑, or only direction
only direction if saturated
Zeeman effect
|BLOS|,|BPOS|, 𝜽POS
very weak in the corona
Gyroresonance
|B|
only in strong-field regions (now)
Bremsstrahlung
|BLOS|
in a single solar layer
coronal seismology
|B|, 𝜽POS direction
depends on assumed wave mode
Faraday rotation
limited LOSes available
flaring radio emission
Type II, III, etc
intermittent in time
“We’d like to ingest all these [incomplete] measurements into an amazing piece of code...” [to get full B(x,y,z,t)]
no one technique has all the information. but they all sample slightly different plasma, even at the same location, so we have to be careful about combining.
each technique has its own drawback either limited info/limited sampling/weak signal/etc.
Forward modelling lets you see what information each technique would provide and give a work-space for combining this information in various ways. obviously there are still assumptions that are made, about the other plasma parameters (density, temp, filling factor, etc) and about the methods (i.e. the physics behind the emission/scattering/level populations/etc.
tried to put the most well-known in here, but its not an exhaustive list
many will be used in this session’s talks and posters. You will hear about FORWARD, and IDL set of codes that does create the synthetic obs data for several of these observations.
laser plasmas in the lab, laser corona studies.
flaring radio emission - type 1,2,3, bursts, generally associated with CMEs
scintillation is mostly for density, for cmes
doppler: pos B strength
craig’s method? with heliospheric imagers?

7. All-around Challenges
The magnetic field parameter is entangled with plasma parameters
The magnetic field changes on space/time scales smaller than the observations
Estimation of the true error of the inversion involves many sources, some not easily quantifiable.

8. All-around Challenges
The magnetic field parameter is entangled with plasma parameters
The magnetic field changes on space/time scales smaller than the observations
Estimation of the true error of the inversion involves many sources, some not easily quantifiable.
“...backing into the chromosphere slowly... it’s a very scary place.” --- Tim Bastian

9. Schedule
2:00 – 3:15:
Brief introduction from session organizers (this!)
Scene-setting talk #1: Laurel Rachmeler, NASA/MSFC: “Challenges in Spectro-polarimetric Measurements of the Coronal and Chromospheric Magnetic Field”
Poster summaries: Judit Szente (AwSOM), Paul Song (theory)

10. Schedule
2:00 – 3:15:
Brief introduction from session organizers (this!)
Scene-setting talk #1: Laurel Rachmeler, NASA/MSFC: “Challenges in Spectro-polarimetric Measurements of the Coronal and Chromospheric Magnetic Field”
Poster summaries: Judit Szente (AwSOM), Paul Song (theory)
3:15 – 3:45:
Coffee break
3:45 – 5:00:
Scene-setting talk #2: Jeff Kuhn, U. Hawaii: “DKIST Coronal Spectroscopy: Getting ready for 2020”
Poster summaries: Chris Gilbert (theory), Jonathan Darnel (GOES-16/SUVI), Laurel Rachmeler (CLASP2)
5:00 – ???:
Poster session with refreshments

11. Wanted: Coronal Photons
DKIST
4.2m
IRIS, AIA, COMP 0.2m
SOLARC (Haleakala)
0.45m
COMP (proposed)
1.5m
DKIST: between 10 and 400 times more coronal flux
4m → 105 photons / coronal line / arcsec2 / second

12. Why Haleakala, why the infrared?
Pukalani
& everywhere else?
Haleakala at 4μ
Haleakala
“as good as going to space!”

13. The IR sky, Coronal wavelengths, discovery science
Sky and Corona at 0.1R
(2R)
1994
This slide quantifies what you see from Haleakala with your infrared eyes...
It also shows how the DKIST is in a discovery space. To my knowledge this line is the biggest part of the IR landscape that’s been measured...
There are lines known and predicted that we’ll observe to give a broad range of temperature sensitivity
but...its worth noting that most of the wavelength band from 1 to 5 microns has not been explored
Temperature sensitivity from 3000K to 3MK

14. Lively discussion . . .
Poster contributions on 3D models, new heating mechanisms, & new instrument concepts.
We need better data, better analysis, & better models (*) for interpretation: all in parallel?! (*) Beware: different definitions for “model” exist
Eventually, improved 3D B-field measurements can feed into space weather forecasting models. Data assimilation?
Despite the challenges, there was a lot of optimism!
NSO will be hosting workshops to develop DKIST Science Use Cases in preparation for first light (2020).