3. DATES COVERED (From - To) 29 Sep-3 Oct TITLE AND SUBTITLE. K. S. Balasubramaniam

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1 REPORT DOCUMENTATON PAGE Frm Apprved OMB N Publc reprtng burden fr ths cllectn f nfrmatn s estmated t average 1 hur per respnse, ncludng the tme fr revewng nstructns, searchng exstng data surces, gatherng and mantanng the data needed, and cmpletng and revewng ths cllectn f nfrmatn Send cmments regardng ths burden estmate r any ther aspect f ths cllectn f nfrmatn, ncludng suggestns fr reducng ths burden t Department f Defense, Washngtn Headquarters Servces, Drectrate fr nfrmatn Operatns and Reprts ( ), 1215 Jeffersn Davs Hghway. Sute 1204, Arlngtn, VA Respndents shuld be aware that ntwthstandng any ther prvsn f taw. n persn shall be subject t any penalty fr falng t cmply wth a cllectn f nfrmatn f t des nt dsplay a currently vald OMB cntrl number PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 3 Oct REPORT TYPE Reprnt 3. DATES COVERED (Frm - T) 29 Sep-3 Oct TTLE AND SUBTTLE 5a. CONTRACT NUMBER Observatns f Large-Scale Dynamc Bubbles n Prmnences > Q. O 6. AUTHOR(S). de Tm a, Casn 1. E. Berger 2 B.C. Lw 1 A. G. de Wn 1 J. T. Burkeple' 7. PERFORMNG ORGANZATON NAME(S) AND ADDRESS(ES) Ar Frce Research Labratry/RVBXS P. O. Bx 62, Natnal Slar Observatry Sunspt, NM K. S. Balasubramanam 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER e. TASK NUMBER RD 5f. WORK UNT NUMBER Zl 8. PERFORMNG ORGANZATON REPORT NUMBER AFRL-RV-H A-TR SPONSORNG / MONTORNG AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONTOR'S ACRONYM(S) AFRL/RVBXS 11. SPONSOR/MONTOR'S REPORT NUMBER(S) 12. DSTRBUTON / AVALABLTY STATEMENT Apprved fr Publc Release; dstrbutn unlmted 13. SUPPLEMENTARY NOTES: REPRNTED FROM: Astrnmcal Scety f the Pacfc Cnference Seres, Vlume 415, Secnd Hnde Scence Meetng, Bulder, CO, ppl63-l , Astrnmcal Scety f the Pacfc. 1. Hgh Alttude Observatry, NCAR, Bulder, CO Lckheed Martn Slar and Astrphyscs Labratry, 3251 Hanver St., Pal Alt, CA ABSTRACT Slar prmnences are very dynamc bjects, shwng cntnuus mtns dwn t ther smallest reslvable spatal and tempral scales. Hwever, as macrscpc magnetc structures, they are remarkably stable durng ther quescent phase. We present recent grund-based and Hnde bservatns f large-scale bubble-lke, dynamc sub-structures that frm wthn and rse thrugh quescent prmnences wthut dsruptng them. We nvestgate the smlartes and dfferences f the Hnde and grund-based bservatns and dscuss ther mplcatns fr mdels f prmnences. 15. SUBJECT TERMS Sun Slar actvty Slar bservatns 16. SECURTY CLASSFCATON OF: a. REPORT b. ABSTRACT Slar atmsphere Slar mdels c. THS PAGE Slar magnetc felds 17. LMTATON OF ABSTRACT UNL Slar eruptns Slar prmnences 18. NUMBER OF PAGES 19a. NAME OF RESPONSBLE PERSON K. S. Balasubramanam 19b. TELEPHONE NUMBER (nclude area cde) Standard Frm 298 (Rev. 8-98) Prescrbed by ANS Std

2 THE SECOND HNODE SCENCE MEETNG ASP Cnference Seres, Vl. 415, 2009 B. Ltes. M. Cheung, T. Magara, J. Marska, and K. Reeves Observatns f Large-Scale Dynamc Bubbles n Prmnences 23b , 417 < C\J - < > a: LL < he a Mare nuuty's : G. de Tma, 1. R. Casn, 1 T. E. Berger, 2 B. ('. Lw, 1 A. G. de Wjn, 1 J. T. Burkeple, 1 and K. S. Balasubramanam' ' Hgh Alttude Observatry, Natnal Center fr Atmspherc Research, P.O. Bx.WOO, Bulder, CO , USA 2 Lckheed Martn Slar and Astrphyscs Labratry, 3251 Hanver Street, Pal Alt, CA 94304, USA 3 Ar Frce Research Labratry, Natnal Slar Observatry, Sunspt, New Mexc, USA Abstract. Slar prmnences are very dynamc bjects, shwng cntnuus mtns dwn t ther smallest reslvable spatal and tempral scales. Hwever, as macrscpc magnetc structures, they are remarkably stable durng ther quescent phase. We present recent grund-based and Huxe bservatns f large-scale bubble-lke, dynamc sub-structures that frm wthn and rse thrugh quescent prmnences wthut dsruptng them. We nvestgate the smlartes and dfferences f the Hmde and grund-based bservatns and dscuss ther mplcatns fr mdels f prmnences. Observatns f Bubbles wthn Prmnences Quescent prmnences f the "hedgerw" type are knwn t have a flamentary structure and dwnflws. They als ften shw quas-statnary, dark, cnvex regns at ther base. The Slar Optcal Telescpe (SOT) n-bard Hmde (Tsuneta et al. 2008) prvdes bservatns f prmnences frm space wth an unprecedented spatal reslutn f abut 0.2"and tempral cadence f less than 30s shwng that prmnences are very dynamc dwn t ther smallest reslvable scale. These new bservatns led t the dscvery f small-scale, cntnual upflws n the frm f dark turbulent plumes (Berger et al. 2008; see als Berger et al. n ths vlume). At these hgh spatal reslutns, macrscpc curtan-lke prmnence structures are seen t be cmpsed f vertcally rented flaments f plasma wth wdths f nly a few hundred klmeters that are separated by dark vertcal lanes f cmparable wdths. Typcally, the brght flaments shw cntnual dwnward mtns, whle rregular dark plumes are seen t rse upward wth velctes f abut km s _1 (Berger et al. 2008). Hmde /SOT has als bserved a few cases f large, bubble-lke features at the base f quescent hedgerw prmnences. We reprt n tw events n Aprl and August 16, 2007, when these bubble-lke structures n prmnences were bserved smultaneusly n Ca 11 A3968 and Ha fr several hurs. These large and dark bubbles frst grew quas-steadly, then rse and appeared t push the brght prmnence plasma asde n rder t travel tpward, reachng a sgnfcant heght wthn the prmnence befre lsng ther rund shape. These hgh-cadence blrvatns are nterestng t cmpare wth recent grund-based bservatns f mre dynamc bubble events n quescent prmnences (de Tma et al. 2008)

3 164 de Tma et al Hnde Observatns On Aprl 25, 2007 Hnde/SOT bserved a relatvely dark, arched regn rmmwj wth a thn brght bundary at the base f a quescent prmnence. Ths bubbfelke regn was quas-statnary at frst and after 1330 UT started t mve upward acceleratng up t 5; km s - '. The bubble brke up lsng ts shape befre reachng the prmnence tp. Ths bubble had relatvely lw cntrast Sgnfcant sub-structures, ncludng dark upflwng plumes and brght dwn- Hws, were ntceable "'nsde" the bubble. Because these bservatns are affected by lne-f-sght ntegratn, and the full 3-dmensnal gemetry f the bubbles s nt knwn, we cannt tell whether these sub-structures were part l the bubble tself r smply unrelated structures alng the same lne-f-sght 2'HJ. UN-d.. JO 200/ 08 )( 1." 13 1?MT 2007(1 f. '' V '1 200/ UT H M 55. Aucult S y f-.,»**' n-: j....»--< -* lfl ' Tm* (hurs Fgure 1, H mages taken wth Hnde/SOT. shwng the rse, break-up, and subsequent refrmatn f the bubble n August (tp three rws). Nte that the bubble shape changed as t mved upward. We als shw the trajectry f the bubble durng ts fast ascent (bttm left), and a lwer-reslutn mage f the bubble taken at MLSO (bttm rght). The bubble bserved n August 16, 2007 (Fg. 1) was lnger lved, wder. and had hgher cntrast than the ne f Aprl 25. The bubble was seen t slwly j grw n sze and rse. Durng ts ascent, ts apparent wdth ncreased frm less than 40" t abut 55". The bubble's brght bundary at tmes lst defntn. and the bubble appeared t be at the pnt f break-up. but then restructured ts'lf t ts rgnal shape. Arund 1900 UT the suthern end started t acceler-!

4 Large-Scale Dynamc Bubbles n Prmnences 165 ate reachng a velcty f abut 20kns -1 and a heght f ~ 56" befre breakng up at w 1923 UT. nterestngly, the bubble was seen t refrm at. abut t he same lcatn abut 90mn after t brke, and started t slwly rse and grw agan reachng up t 65" n wdth Grund-Based Observatns :&*.H ^^ *Mt T! % PM 1^" Wr^ ^65>-rv' ' M ^fcj (* '.^^k 1321 UT 826UT 1331UT ljdut 1841UT l:6ut 829UT 832U1 184/UT 18S0U m H/ ^ htm-ack U'T1 u On KJ twr.1.) Hc< tn... j bana H* ' Whbttl 'J H' UK.'Jfl led'u Fgure 2. Ha mages taken wth wth the mprved Slar Observng Optcal Netwrk (SOON) at NSO/SP (tp) and wth the Plarmeter fr nner Crnal Studes (PCS) at MLSO (bttm) n Nvember 8, The tp mages, taken 5 mn apart, shw the detals and evlutn f the brght cre nsde the bubble us t apprached the bubble tp. The bttm mages, taken durng the early (left three panels) and late (rght tw panels) phase f the event, clearly shw the brght frnt and the neckng f the bubble. On Nvember 8, 2007 an unusual and dynamc event n a slar quescent prmnence was bserved n Ha (656.3 nm) and He 1083 nm wth the nstruments f the Mauna La Slar Observatry (MLSO) and at the Natnal Slar Observatry/Sacrament Peak (NSO/SP). A large-scale, dark bubble wth a brght cre rse vertcally thrugh the prmnence wthut causng t t erupt (Fg. 2). The bubble had an apprxmate wdth f 40", and mved upward frm the prmnence base at an average speed f 12kms _1. t frmed a brght frnt, lkely due t cmpressn f prmnence materal, as t traversed the prmnence up t the tp. A cmpact and brght cre develped nsde the bubble and was seen t accelerate frm 12 kms"' t abut 20 bs" 1, leavng a thn tral f materal behnd. The bubble changed ts shape durng the rse, assumng a 'keyhle" shape befre fadng frm vew. A secnd elngated, dark bubble was als seen t rse at the nrth edge f the prmnence almst smultaneusly t the frst ne. Als n ths case, we culd see flamentary dwnflws smlar t thse bserved n the Hnde events descrbed abve. A-srnnarTrynaTntcrbTrfrble^b^ cre, was bse'vwr~at~ MLSO n Aprl 6, As n the prevus event, a dark bubble was seen t rse upward, traversng mst f the prmnence, and fnally evlvng nt a key-hle shape befre fadng.

5 160 de Tma et a Dscussn The events descrbed abve a large-scale, bubble-lke dsturbance mvng thrugh a quescent prmnence wthut causng ts eruptn - pse several nterestng physcal questns n the nature f prmnences. n spte f the fact that these dark bubbles were cmparable n sze t the prmnences, ther nly effect was t dsplace the prmnence plasma leavng the verall shape f the prmnence very smlar t that befre the event. What s the hydrmagnetc nature f ths remarkable stablty f quescent prmnences? The cntnuus presence f rsng, vertcally elngated dark plumes amdst generally descendng, narrw vertcal brght flaments make us wnder f the stablty f the macrscpc structure s dstnct frm the ne that permts the unstppable rse f a larger-scale, dark bubble up thrugh the entre prmnence. t s nt clear f the bubbles bserved by Hnde and at MLSO are the same physcal phenmenn. They have several smlartes: ther szes (20-60"), rund shapes, relatve darkness, and velctes (10 20kms ). They als have sgnfcant dfferences: the Hnde bubbles were relatvely mre statnary, lngerlved, and, n ne case, the bubble refrmed at the same lcatn. The MLSO bubbles were mre dynamc, had hgher cntrast, a brght cre, and a brght frnt that suggests the effect f dynamcal cmpressn. What s the physcal nature f these bubbles? One pssblty s that they are rganzed, clsed magnetc structures whse strnger magnetc pressure makes up fr the lwer gas pressure f ts lw-densty nterr. Such structures may persst n quas-statc evlutn untl a large-scale recnfguratn s necessary fr the prmnence t fnd the next avalable quas-statc equlbrum, as suggested by hydrmagnetc mdels (e.g.. Frbes and senberg 1991). Alternatvely, these bubbles can be hgh-temperature plasmas, prduced by sme dynamcal heatng, that rse cnvectvely thrugh the macrscpc magnetc structure (Berger et al. 2008). We beleve these phenmena mert further bservatnal and theretcal nvestgatn. The answers t these questns are needed fr a cmplete physcal understandng f quescent prmnences, frm ther brth, thrugh quassteady evlutn, t eventual eruptn n asscatn wth a crnal mass ejectn. Spectr-plarmetrc bservatns are essental t understand the magnetc nature f prmnences and ther sub-structures. n the case f the fast evlvng events descrbed here, magng spectr-plarmetry s t be preferred. Whle stll challengng, ths type f measurements are wthn reach f present-day nstrumentatn (e.g.. wth Arcetr/NSO/BS), and shuld actvely be pursued. Fr ths purpse. HAO s prpsng the cnstructn f a dedcated nstrument (ClrMag) t measure clrmspherc magnetc felds and flws. Acknwledgments. MLSO s an NCAR faclty perated by the Hgh Alttude Observatry. \SO s perated by the Asscatn f Unverstes fr Research n Astrnmy nc. fr the Natnal Scence Fundatn. NCAR s spnsred by the Natnal Scence Fundatn. References Berger, T. E.. et al Ap.. 076, L89 dc Tma, G., Casn, R... Rurkeple, J. T., and Lw, B. C. 2008, Ap.. 687, L123 Frbes, T. G., and senberg, P. A. 1991, ApJ, Tsuneta, S., et al. 2008, Sla! Phys