Themis-SWT workshop, Apr.2008 December 27, 2007 ~2130 & 2220UT Simultaneous THEMIS observations near the inner and outer plasma sheet boundaries in the. - презентация

1 Themis-SWT workshop, Apr.2008 December 27, 2007 ~2130 & 2220UT Simultaneous THEMIS observations near the inner and outer plasma sheet boundaries in the near tail at substorm onset V.Sergeev, S.Apatenkov (SPbU), V.Angelopoulos (UCLA) & THEMIS team, N.Partamies (FMI), … PURPOSE : Simultaneous probing of inner region and BLPS/lobe at ~11Re during ideal onsets & ideal observing conditions Constraints for SBS onset models

2 Themis-SWT workshop, Apr.2008 December 27, 2007 THEMIS – MIRACLE\Image conjunction Configuration: near-radial alignments of P1 and P2 near midnight - simultaneous probing of inner magnetosphere (P2) and of lobe/PS interface (P1) Location: P1 & P2 in the same meridional plane, inside of the SCW sector (from midlatitude bays) Task: provide constraints to identify substorm onset mechanism (where & how)

3 Themis-SWT workshop, Apr.2008 December 27, 2007 THEMIS – MIRACLE\Image conjunction (2) Moderate substorm SW Image AE Midlatitude bays ( SCW) +Pi2 Auroral expansion 67 o 72 o Dipolarizations at both P1 & P2 Injection to GEO

4 Themis-SWT workshop, Apr.2008 December 27, 2007 THEMIS (3) P1 P2

5 Themis-SWT workshop, Apr.2008 December 27, 2007 THEMIS (4) Earliest Onset at Lobe/Plasma Sheet interface (11-12 Re): Unloading (10% drop of Ptot) Dipolarizationstarts (Bz) Dissipation and intense Flux Transfer (+Ey ) Fast upward convection of Frozen-in plasma tubes Fast plasma sheet thinning, P1 exit to the lobes At the lobes: Intense flux transfer continues; 1min scale Impulsive Mode (NFTEs, Bz Ey Vz) monoenergetic drifting ions Plasma sheet expansion: no associated downward Vz, expansion into empty tubes,

6 Themis-SWT workshop, Apr.2008 December 27, 2007 THEMIS (5) Onset at P2, inner Plasma Sheet (~8 Re): Major dipolarization/injection delayed by 1-2 min after P1 onset Injection precursors (soon after onset at P1) : weak Earthward flow pulse and smooth pressure increase During dipolarization: erratic flux transfer; ~1min scale observed E-flow bursts in association with Bz increase and Ptot drops (bubble signatures?) Azimuthal plasma flow: comparable to E/T flows flow toward dusk (dawn) in duskside 1 st (dawnside 2 nd ) half of SCW flow diversion P1

7 Themis-SWT workshop, Apr.2008 THEMIS – MIRACLE conjunction, results from Dec.27, 2007 events Features of onset instability from a different perspective: Earlier at >11Re, delayed by 1-2min at ~8Re;( In Out, Out In) ~5-10% Total Pressure drop at >11Re (unloading); high flux transfer rate of a few mV/m (Ey) (~frozen-in in the lobes) ; fast flow inward (toward the NS) from the lobes (1Re/min!) and PS thinning during outward (poleward) auroral expansion (plasma motion through the separatrix? ); PSBL is cold/dense during fast PS Thinning (thinning associated with inward flow & explosive growth of TCS?, XNL at closed FLines) PSBL is hot/rarified during fast PS Expansion (plasma acceleration through the separatrix, Lobe Reconnection? ); Fast thinning + Dipolarization – a non-trivial combination, distinctive property for the choice of substorm mechanism No room for CD in the inner region. Impulsive reconnection (started on closed FL), XNL a few Re from P1??

8 Themis-SWT workshop, Apr.2008 Global 3d MHD simulation results Could/Where dipolarization+thinning be predicted? - In case of near-Earth (neary) reconnection, before the onset of lobe reconnection

9 Themis-SWT workshop, Apr.2008 E N D

10 Themis-SWT workshop, Apr.2008 THEMIS – MIRACLE conjunctions : Dec.27, 2007 events Fast PS thinning at ~11Re simultaneous with decrease of lobe pressure (CD) and Bz increase and poleward auroral expansion !! monitoring lobe-PS interface, heated PS at expansion (lobe reconnection in progress) Earthward propagation 11Re 7-8 Re 6.6Re Further work on plasma streaming etc, Lobe signatures (NFTEs) thB, E-field and B-plasma correlations at C, close to magn. Equator. Nature of structuring, Interchange/balloons etc… Potentially interesting for Pi2 studies BCBC inj to 6.6

11 Themis-SWT workshop, Apr.2008 THEMIS – MIRACLE conjunctions : Dec.27, 2007 events C - close to magn. Equator Structured plasma – Interchange/Balloon. Instability?

12 Themis-SWT workshop, Apr.2008 THEMIS – MIRACLE conjunctions : Jan.04, 2008 events 3 SC Weak activity multiple activations SCW+Pi UT thB in the lobe, good for testing SCW module

13 Themis-SWT workshop, Apr.2008 THEMIS – MIRACLE conjunctions : one example - Dec.27, 2007 events (2) SW trigger?? – Cluster Some auroral data exist (LYR) EISCAT ? CUTLASS ?

14 Themis-SWT workshop, Apr.2008 THEMIS – MIRACLE\Image conjunctions Recent injection event list Dec. 19, 2007 ~2120? Dec. 23, 2007 ~2115? Dec. 27, , ~2220, LYR Dec. 31, 2007 ~2010 … MUO,LYR,201243PolarUVI Jan. 04, 2008 ~2024, 2126 Q Jan. 08, 2008 ~2100, 2130, Mostly weak events (PBU-like), easier for studies with radars

15 Themis-SWT workshop, Apr.2008 Observation-based Tuning of Magnetospheric Models for ТНЕМIS

16 Themis-SWT workshop, Apr.2008 Mapping Mapping ionosphere magnetosphere - essential part of THEMIS ( THEMIS = 5 SC + dense conjugate ground network ) How to do? Routine application of standard models Change/tune models to achieve best accuracy possible Standard tools available – Empirical models (T96, T01, T03,TS05...) parametrized by solar wind/activity (Pd, By, Bz, Dst) input Problems? SW data are delayed SW data may not be accurate (inhomogeneous SW, wrong time shift, …) Model often inadequate for unusual/extremal configurations which often are the most interesting to explore Which (of different!) models works best?? General problem--What is the mapping accuracy?

17 Themis-SWT workshop, Apr.2008 Adapted models for THEMIS, our approach THEMIS has a large potential for tuning/adapting the model using in situ magnetic observations 5SC, cover large distance range (10-30Re), allow to resolve amplitudes of different components (RC, tail modules, etc) in the model; may include data of other magnetospheric SC (GOES, Geotail,..) and additional resources (Isotropic Boundaries, plasma pressure etc, e.g., Kubyshkina et al., JGR 2002) our approach - combine careful modeling of individual events (by expert) with routine processing (tuning) A simple approach selected for routine procession in THEMIS Main ideas : Use standard models as a tool to interpolate B observed at 5(+) SC Treat SW parameters as input parameters of the model varying to obtain best fit to observations Restrain from changing internal parameters of models (to avoid unphysical effects, examples later..) Use SW flow deviation angle as additional free variable Output for users – Pd, Bz, By, Dst, to use with GEOPACK-2007

18 Themis-SWT workshop, Apr.2008 Testing the routine tuning algorithm Current state of activity Test on synthetic events Use THEMIS predicted orbits and past SW data (Feb.25-27, 2008/2001) Simulate observed B from T01 model, reconstruct using T96 model

19 Themis-SWT workshop, Apr.2008 Testing the routine tuning algorithm (2) Tests on real events before Dec.15 – bad X-coverage January 2008 data (in progress) – An example of Jan.06,2008 (Qday) No Tilt, … Compare mapped footpoint latitudes for standard T96 and 2 tuned model codes Deviations up to >5 degrees. Larger deviations if using tilts as free parameter /which part is real??/ … (pressure test/usage in tuning) Still in working stage…

20 Themis-SWT workshop, Apr.2008 Beta-version of the new release of the Geopack-2007 fortran package /by N.Tsyganenko/ New features: (i)- includes transformations to and from the GSW (solar-wind magnetospheric) coordinate system. The new version allows one to trace model field lines, taking into account the observed deflections of the solar wind from strictly radial anti- sunward direction. (ii) - the s/r TRACE was modified by adding 3 new input parameters, to make it more 'tunable', (iii) - a new subroutine GEODGEO was written and added to the package, converting geodetic coordinates to geocentric and back. Available at Updated Geopack-2007 fortran package

21 Themis-SWT workshop, Apr.2008 Подстройка (tail season) - версии, режим работы, вывод 1/ Определение версий Т96 (?!) с шагом 5мин (?!), ПРОДУКТЫ : а) В течение недели (1раз \ 4дня??) ТПрогр / РПрог T96-00В (только В THEMIS, =0) 1 \ 0 T96-01В (только В THEMIS, 0) 1? \ 0 б) По получении доп. данных (GOES, Polar??, GT??,…) T96-02В (только В, 0) 1 \ 0 \только особые периоды??\ в) По получении калибр. давлений (1мес???) T96-03Р (Р + В, 0) 0? \ 0 г) По получении данных СВ со сдвигом?? (1мес???) T96-04SW (без подстройки, для исслед. ? ) 1? \ 0 д) Для списка событий () T96-05АМ (тонкая подстройка, для исслед. ???) 1? \ 0

22 Themis-SWT workshop, Apr.2008 Подстройка (tail season) - версии, вывод данных (2) ВЫВОД : -5 * (x,y,z) -5*(Bx,By,Bz) OBS ( 5 SC n SC) -Параметры модели Т96 (Pd,Dst,Bz,By, ) -? ИСФПроекции N из (-6.6, 0, NS), (-10, 0, NS)?, (-15, 0, NS), - веса характ. геометрию, -? Рпл Ограничения: а) только при R>4Re; веса в близкой группе (как индекс геом.проблем) б) Нужно предоставить тексты программы реализующей работу с поправкой

23 Themis-SWT workshop, Apr.2008 Подстройка (tail season) - задачи (3) 1/ Определение версий Т96 (?!) с шагом 5мин (?!), ПРОДУКТЫ 2/ T96-05АМ - тонкая подстройка, для отд.моментов - иссл. магнитосферного очага аврор.брейкапа -иссл. Авроральной проекции области пересоединения перед началом взрыва, -Характерные конфигурации СМК и суббурь… 3/ Исследования с помощью подстроенных моделей -Качество стандартных моделей (в т.ч. по данным СВ); оценка точности проекций; -Сравнительный анализ конфигураций СМК и суббурь; -Динамика глобальных параметров (BL, FT, проекции…) в суббурях; - -Исследование SCW модуля магнитосферной модели

24 Themis-SWT workshop, Apr.2008 Testing a simple tool : Mapping latitudes Compare performance of T96 and T01 models, and accuracy of reconstruction/mapping by using T01 model as input and reconstructing parameters of T96 Reasonable quality of mapping (

25 Themis-SWT workshop, Apr.2008 A simple tool for mapping : Conclusion Usage of T01/T96… models as interpolation/extrapolation tool : provides reasonable reproduction of magnetospheric B-field and satisfactory (

26 Themis-SWT workshop, Apr.2008 Advanced tool : assimilative data- tuned model Choice of a model to modify: (any model with free parameters) A : Pulkkinen T.I., A Study of magnetic field and current configurations in the magnetotail at the time of the substorm onset, Planet.Space Sci., Kubyshkina M.V. et al., Hibrid Input Algorithm:An event oriented magnetospheric model, JGR, Used T89 with modifications inserted: Additional tilt of the neutral sheet (1 free parameter) Ring current enhancement (1 free parameter) Surface currents enhancement (1 free parameter) Tail current enhancement (1 free parameter) Tail current thinning: (5 free parameters) Including an additional thin current sheet of the similar geometry (5 free parameters)

27 Themis-SWT workshop, Apr.2008 Input data for modelling Main source:B-field measured at spacecraft - Usual problem - lack of data : too few spacecraft in occasional positions Possible solutions: A: use time-varying models with predetermined behaviour of free parameters (linear) T. Pulkkinen, G. Lu et al. B: add to magnetic field data all the possible measurements that may be reproduced from the adjusted model (Kubyshkina et al, Ganushkina et al.) This may be: 1) Isotropic boundaries for ions and electrons of different energies:

28 Themis-SWT workshop, Apr ) B angle measured by LANL spacecraft: determines the B-direction as a symmetry axis of temperaure matrix T (angle between symmetry axis and spin axis of the spacecraft). Available if Tpar/Tperp not close to 1: Input data for modelling 3) Pressure value measured at magnetospheric spacecraft. Needed pressure balance across the magnetotail : Blobe observed = 2μ 0 (Pplasma spc +Pmagn spc ) 1/2 Blobe modeled= Bmod(xspc, yspc,zspc+5Re) 4) Pressure measured at low altitude in the region of isotropic presssure needed isotropy of Pressure so that gradP=J B and pressure is conserved along the B-line 5) Dst value but : difficult to take in account all the sources of measured Dst