Thermal Properties of Moving Prominence Features Seen in EUV

Terry Kucera (NASA/GSFC)

Enrico Landi (NRL) and Judy Karpen (GSFC)

Study Goals

• Measure thermal properties of individual moving prominence features and compare them to model outputs, particularly the Dynamic Equilibrium Model

Targets

Apr. 29, 2004 Large prominence between active regions

Apr. 17, 2003 Quiet and Activated Prominence

Apr. 30, 2004 Erupting Prominence

Apr. 30 -May 1, 2004 Quiet and Activated prominence

Data

Ion Wavelength (Å) Temp. (K)

N III 764.34 80,000

N III 763.33 80,000

N IV 765.15 160,000

S V 786.47 160,000

O IV

O V

787.715

760.43,760.21

200,000250,000

O V 761.13 250,000

O V 761.99 250,000

Ne VIII 770.42 630,000

Mg VIII 782.34 790,000

Mg VIII 762.65 790,000

S X

S XI

787.558

783.01

1,000,0001,500,000

SOHO/SUMER2" resolution, 120" slit length90 sec cadence Waveband Sources of

EmissionTemp. (K)

20,000 1216 Å Ly

1600 Å C IV 100,000

C I, Fe II, Si Cont.

4,000-10,000

195 Å H & He continuum absorption,

10,000-30,000

Fe XII 1,500,000

TRACE1" resolution, 60-91 sec cadence

Global Hα Network1.1 resolution, 1 min cadence6563 Å H 10,000

DEM techniqueLandi & Landini 1997Assumes:

Ionization EquilibriumOptically thin plasmaSmooth function (spline)

Also:No material below 104 K or above 108 KCoronal abundances

Does not trust points below LogT=4.4 (ionization fraction problems - charge transfer not well understood)

or Na or Li -like ions (ionization fraction not sufficiently well understood)

We tried where possible to subtract off or compare to a background component

DEM comments

In general these curves tend to look pretty similarThey are different in many details from other prominence DEMs

Transition region temperature lines pretty goodBig gap between O V (LogT 5.4) and Ne VIII ( LogT 5.8)Ne VIII lines the only really strong ones for LogT≥5.8

Typical DEM

Typical DEM background subtracted

Comparison of SUMER and CDS

Dynamic Equilibrium Model

Karpen & Antiochos 2008.

Karpen & Antiochos 2008

Typical DEM background subtracted

Data Results

•Prominence DEMs uniform for T< 250,000 K from on prominence to the next, but with minimum at higher temp than prominence DEMs from other studies.

•For T>250,000 K (i.e., Ne VIII) the amount of emission varied

•DEMs of individual moving features show the same high slope at low T seen in DEMs taken over prominences over longer periods of time, so a model in which this portion of the DEM is replicated by many sources is not adequate.

Dynamic Equilibrium Model comparison

Previously Karpen & Antiochos (2008) showed that the average of a long run of the model could be successfully compared to DEM spectra taken over long time periods.

Here we see that the DEM of a short run of the model (5 min) exhibits the same shape, so a single moving feature in the model exhibits high amounts a material in the low temperature TR.

High temperature TR curve is consistent with “background subtracted” DEMs.

Differences with individual feature DEMs Temp minima