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HINODE Operation Plan (HOP)

accepted on


 HOP No.

 HOP title

HOP 0105

He II lines in quiescent prominences

plan term


@ @


 name : Vial, Berger, Culhane, Curdt, Ebadi, Labrosse, Parenti, EIT, TRACE, XRT @  e-mail : jean-claude.vial[at]ias.u-psud.fr

contact person in HINODE team

 name : Berger @  e-mail : berger[at]lmsal.com

 abstract of observational proposal
The objective of this proposal is to build a prominence diagnostic focused on some HeI-HeII in conjonction with H lines. Although prominences (as other solar features) are daily observed in  He II (30.4nm) with EIT/SoHO, not many studies have been devoted to the emission of He (I and II) in conjonction with H lines in prominences, in contrast with the modelling performed by Labrosse et al. which now includes velocity effects (Labrosse et al. 2007, 2008). There are various reasons for that, including the fact that the various lines are located in rather distant wavelength ranges, which impedes simultaneous observations.
This drawback can (partially) be solved if one uses a set of He II lines which are located in the blue wings of the Lyman series (see the Parenti at al. 2005 Atlas). As discussed by Ebadi et al. (2008), these lines are actually the even  
Balmer lines of He II and they have been measured up to L10.

The above-mentioned measurements are unfortunately characterized by :
* a dispersion in time and objects
* a difficult (impossible ?) detection of the first even Balmer He II line (2p 2P3/2-4d 2D3/2) when the SUMER attenuator is used to record the Lalpha line.

The objective of this JOP/HOP is to record clean He I, II and H lines on the same feature within a time interval as short as possible.

A first version of the JOP/HOP consists in getting the first even Balmer line in a proper way (WITHOUT the Lalpha attenuator) along with the following line located in the Lbeta line wing in order to have a reference with respect to previous measurements (Ebadi et al. 2008).

Other H and He lines are of great interest. We recall here that the lower level of the Balmer lines is just the upper level 2P3/2 of the resonance He II 30.4 nm line.

We also recall that the ionization properties of prominences are essentially determined by H which requires the Lyman lines to be  recorded and computed.

References :
H. Ebadi, J.-C. Vial, A. Ajabshirizadeh, 2008, The HeII and DI lines in the Lyman series profiles of solar prominences, accepted in Solar Physics

Labrosse, N., Gouttebroze, P., and Vial, J.-C., 2007, Effect of motions in prominences on the helium resonance lines in the extreme ultraviolet, Astronomy and Astrophysics, 463, 1171

Labrosse, N., Vial, J.-C., Gouttebroze, P., 2008, Diagnostics of active and eruptive prominences through hydrogen and helium lines modelling, Ann. Geophys., 26, 2961

S. Parenti, J.-C. Vial, P. Lemaire, 2005, Prominence Atlas in the SUMER range 800 - 1250 A II. Line profile properties ans ions identifications, Astron. and Astrophys., 443, 685

 request to SOT
Prog. 0x01bf
NFI: H }208mA DG, 1408x1408, 2x2 sum, 500 msec exposure.
BFI: Ca II H-line, 2K x 2K, 2x2 sum, 500 msec exposure.
ROI shift for off-limb.  Cadence = 20-30 seconds.

 request to XRT
RT Al_poly or C_poly images

 request to EIS
Study 168 (CAM_ARTB_RHESSI_b_2) preceded and followed by Study 235 (PRY_slot_context).
Overall duration is less than 60 minutes and should be OK with SUMER study
(about 80 minutes). It should start about 20 minutes after the beginning of

 other participating instruments

The pointing should aim at a quiescent prominence. CDS, SUMER and EIS studies include QS (and limb) regions at close observing times (not necessarily within the program itself). The duration of the JOP/HOP is limited by the SUMER capability of observing the Lalpha line free of attenuation. So a set of twice or three-times one-hour sequences should be OK.

SUMER: The program should be based on LYA_B_RASTER but with a smaller raster  
(12 arcsec wide). The sequence is :Lalpha -> Lbeta (+ O VI) -> spatial step -> Lbeta -> Lalpha -> step ..
Only 50 spectral pixels are selected (with two spectral positionings for Lalpha).
Slit 0.3" x 120"
Two rasters (within a few hours from the promience observations) at a quiet limb and in a QS region.
The SUMER program is in preparation.

CDS: A context raster, 140" by 140", (which should provide information on both quiet limb and quiet Sun) including  He II 304 A (2nd order),  He I 584 A and several strong lines at different temperatures. Then a series of smaller rasters, 40" by 140", using the same lines.
The CDS study is in preparation.

EIT : At least one full Sun 30.4 image during the SUMER/CDS/EIS observing time

TRACE : A sequence of Lalpha images centered on the prominence during the SUMER/CDS/EIS observing time

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