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CDS active region results

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Intense transition region brightenings

• Oxygen and neon lines enhanced over q.s. by factors ≳ 20• Photospheric abundances (Young & Mason 1997)• Velocity shifts?• Line broadenings?

Files584

RegionQS

O V intensity299

s3072s10962s3484

ARARAR

183101270010070

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Intense transition region brightenings

• Signatures:– Strong continuum (scattered Ly-alpha?)– O IV 625.8 strong ( high densities)– No response from corona

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Blinkers

• Parnell et al. (2002) extended blinker study of Bewsher et al. (2003) to active regions

• Properties are very similar, except– More frequent (up to 7 times more)– Intensity enhancement higher (up to factor 3)– Coronal response in some cases

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Oscillations

• Typical feature of transition region above sunspots (Fludra, Brynildsen, etc.). ~3 min period

• Other active region: Ireland et al. (1999), O’Shea et al. (2001)– 5 min oscillations most common photospheric driver– Mg IX, Fe XVI: more significant oscillations in velocity than

intensity

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Large TRACE loops

• Ubiquitous feature of TRACE 171 images of active regions• Often show strong Mg/Ne enhancement in CDS data• Footpoint density (Mg VII) is around 1010 cm-3

• Leg density (Si X) is around 108.5 cm-3

• What is relation to sunspot plumes?

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Mg VI

Mg VII

Si VIIIMg IXMg X

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Sunspot Plumes

• “A sunspot plume is observed if the contours for peak line intensity are located with a considerable fraction of the emission inside the white light sunspot.”– Brynildsen et al. 1999, Sol.Phys. 186, 141

• Very weak coronal emission usually seen above sunspots, sunspot plumes not visible in corona

• Are sunspot plumes the footpoints of TRACE loops?

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Active region structure

• Small active regions have a core-halo structure (Gallagher et al. 2001, Mason et al. 1999)

• High temperature (Fe XVI) core, with high density ~1010

cm-3

• Pressure falls off around this core

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Dynamic transition region loops

• Loops seen in, e.g., O V above the limb are very dynamic– Doppler shifts 50-300 km/s

• Independent of coronal loops• Can only be seen at limb! (Intensity is lower than average

QS)

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Coronal loop structure

• Controversial!• TRACE/EIT analyses give isothermal loops• Brkovic et al. (2001) find isothermal with CDS• Schmelz et al. (2002) do not find isothermal with CDS

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Flare Observations

• Czaykowska et al. (1999) presented velocity measurements in O V, Fe XVI, Fe XIX in a flare

• What else can be obtained from CDS observations?