1. Determination of 3D structure, avg density, total mass and plasma properties of an EUV filament observed by SoHO/CDS, SoHO/SUMER and VTT/MSDP Pavol Schwartz Astron. Inst., Academy of Sci. of the Czech Rep., Ondřejov, Czech Republic Peter Heinzel Astron. Inst., Academy of Sci. of the Czech Rep., Ondřejov, Czech Republic Brigitte Schmieder Observatoire de Paris, Section Meudon, Meudon, France

2. H  filament full-disk observations MEUDON H  full-disk observations 15 October 1999 area of CDS observations

3. SoHO/CDS observations of the EUV filament made on 15 October 1999 MgX 624.94 Å SiXII 520.60 Å SoHO/CDS observations of two EUV coronal lines H  observati- ons made by VTT/MSDP (Schwartz et al., 2004)

4. intensity decrease of TR and coronal EUV lines in an EUV filament is caused by: Absorption by resonance hydrogen & helium continua in a cool filament plasma (coronal and TR lines with wavelengths lower than 912 Å) volume blocking ─ volume of an EUV filament is not occupied by hot coronal plasma unlike surrounding corona therefore EUV coronal lines are not emitted from this volume

5. Absorption of EUV line radiation by resonance hydrogen & helium continua in a cool filament plasma 912Å 504Å 227Å HI HeIHeII CDS SUMERCDS EIT + TRACE wavelength MgX 625 ÅSiXII 521Å OV 630Å H Lyman lines 912 ─ 1216 Å OVI 1032Å coeff. of absorption

6. Why are EUV-filaments more extended than their H  counterparts ? Why are EUV-filaments more extended than their H  counterparts ? Because opacity in their extensions in EUV is large enough to be observed as dark structures but in H  is opacity too low.  o (H  ) ─ optical thickness at H  center  (912 Å) ─ optical thickness at H Lyman continuum head d  =  dz H  filament EUV extension (Heinzel et al., 2001)

7. Spectroscopic model intensity at height h normalized to quiet-Sun is defined as f(h);  h  is volume emissivity quiet-Sun intensity as volume emis- sivity integrated along whole line of sight intensity emitted from EUV filament is influenced both by absorption and volume blocking solar surface the top height of H  counterpart can be computed from contribution to intensity from corona above this H  counterpart (Heinzel, Anzer and Schmieder, 2003)

8. 3D structure of EUV extension seen from different view angles (  912 =5) Schwartz et al. (2004)

9. Mass loading into the EUV-filament (approximate estimate) Total mass of EUV filament: 9  10 14 – 3  10 15 g (Heinzel et al., 2004) (for  912 1 – 3) Total mass of CMEs a few times 10 15 g (Webb, 2000) opt. thickness at H Lym. con- tinuum head ~n 1 and geom. thickness D concentration n 2 of H I atoms in 2 nd level proportional to n e 2 ; n e =n p opt. thickness of H  center proportional to n 2 concentration of all hydrogen (neutral and ionized) column mass:m=1.4 m H n H D

10. CDS –SUMER coalignment MgX 624.94 Å SoHO/CDS SoHO/SUMER, L  raster SoHO/CDS position of SUMER slit

11. SoHO/SUMER O VI & CDS O V observations: verifying the SUMER slit position in CDS raster OV and OVI lines correlate well outside the EUV-filament area

12. Spectra of hydrogen Lyman lines in the filament and in the chromosphere observed by SoHO/SUMER on 15 Oct 1999 10:42 ─ 10:56 UT

13. Hydrogen Ly line profiles from quiet chromosphere and from EUV ext. section I full line ─ avg profiles from quiet-chromosphere section on SUMER slit dashed line ─ avg profiles from EUV-extension section I on SUMER slit

14. 1D-slab model of an filament (Heinzel, Schmieder and Vial, 1997) gas pressure P=const turbulent velocity v t  5 km s -1

15. Fitting observed profiles with synthetic profiles  creation of the catalog of synthetic H Lyman profiles using 1D-slab models with different sets of parameters: h 3 and D known from 3D structure and v t =5 km s -1 are kept constant. T c, T s, factor  of steepness of temperature increase/ decrease in PCTR, P, filling factor are changing. The larger  is  the  steeper increase/decrease of temperature in PCTRs occurs and the thinner PCTRs are.  search for the best model in catalog by minimization of  2 of observed and synthetic profiles

16. EUV extension I H ………… h 3 gamma …..  v_t ……... v t fil.fact. …... filling factor tau_o(H_alpha) ….  o (H  )

17. Plasma properties for EUV ext. I across the 1D-slab model

18. EUV extension II

19. EUV extension III

20. Future plans compute bigger and more fine grids of models try to model also profiles from H  filament ─ we know only top height of H  filament therefore its geometrical thickness cannot be estimated use Levenberg-Marquart method for  2 minimi- zation ─ 2 assumptions: computer cluster and need to rewrite code for parallelization More realistic models with more fine structure ─ fibers approximated by multiple 1D slabs

21. The END