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Coronal MHD Waves and Oscillations: Observations and Quests (Invited Review)  

Markus J. Aschwanden   Submitted: 2005-03-03 16:05

Coronal seismology, a new field of solar physics that emerged over the last five years, provides unique information on basic physical properties of the solar corona. The inhomogeneous coronal plasma supports a variety of MHD wave modes, which manifest themselves as standing waves (MHD oscillations) and propagating waves. Here we briefly review the physical properties of observed MHD oscillations and waves, including fast kink modes, fast sausage modes, slow (acoustic) modes, torsional modes, their diagnostics of the coronal magnetic field, and their physical damping mechanisms. We discuss the excitation mechanisms of coronal MHD oscillations and waves: the origin of the exciter, exciter propagation, and excitation in magnetic reconnection outflow regions. Finally we consider the role of coronal MHD oscillations and waves for coronal heating, the detectability of various MHD wave types, and we estimate the energies carried in the observed MHD waves and oscillations: Alfvénic MHD waves could potentially provide sufficient energy to sustain coronal heating, while acoustic MHD waves fall far short of the required coronal heating rates.

Authors: Markus J. Aschwanden
Projects: Soho-EIT,Soho-LASCO,TRACE

Publication Status: Philosophical Transactions of the Royal Society A; Mathematical, Physical and Engineering Sciences, Proc. of The Royal Society S
Last Modified: 2005-03-03 16:05
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Particle Acceleration in Solar Flares and Escape into Interplanetary Space  

Markus J. Aschwanden   Submitted: 2005-03-01 09:38

We review the physics of particle acceleration and kinematics in solar flares under the particular aspect of their escape and propagation into interplanetary space. The topics include the magnetic topology in acceleration regions, the altitude of flare acceleration regions, evidence for bi-directional acceleration, the asymmetry of upward versus downward acceleration, and particle access to interplanetary space.

Authors: Markus J. Aschwanden
Projects: Yohkoh-HXT,Yohkoh-SXT,TRACE

Publication Status: AGU Monograph of AGU Chapman Conference ``Solar Energetic Plasmas and Particles'', Turku, Finland, 2-6 August 2004, (eds. Nat Go
Last Modified: 2005-03-01 09:40
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The Sun  

Markus J. Aschwanden   Submitted: 2005-02-21 15:59

Chapter 1, ''The Sun'' for the ENCYCLOPEDIA OF THE SOLAR SYSTEM. Contents: - Glossary - I. Introduction - II. The Solar Interior - III. The Photosphere - IV. The Chromosphere and Transition Region - V. The Corona - VI. Solar Flares and Coronal Mass Ejections - Final Comments - Bibliography

Authors: Markus J. Aschwanden
Projects: RHESSI,Soho-EIT,Soho-MDI,Soho-CDS,Soho-LASCO,Yohkoh-HXT,Yohkoh-SXT,TRACE

Publication Status: Encyclopedia of the Solar System, 2nd edition, 2005, (eds. Lucy-Ann McFadden, Paul Weissman, & Torrence Johnson), Academy Press,
Last Modified: 2005-02-21 15:59
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2D Feature Recognition and 3D Reconstruction in Solar EUV Images  

Markus J. Aschwanden   Submitted: 2005-01-31 18:38

EUV images show the solar corona in a typical temperature range of T~1 MK, which encompasses the most common coronal structures: loops, filaments, and other magnetic structures in active regions, the quiet Sun, and coronal holes. Quantitative analysis increasingly demands automated 2D feature recognition and 3D reconstruction, in order to localize, track, and monitor the evolution of such coronal structures. We discuss numerical tools that ``fingerprint'' curvi-linear 1D features (e.g., loops and filaments). We discuss existing finger-printing algorithms, such as the brightness gradient method, the oriented-connectivity method, stereoscopic methods, time-differencing, and space-time feature recognition. We discuss improved 2D feature recognition and 3D reconstruction techniques that make use of additional a priori constraints, using guidance from magnetic field extrapolations, curvature radii constraints, and acceleration and velocity constraints in time-dependent image sequences. Applications of these algorithms aid the analysis of SoHO/EIT, TRACE, and STEREO/SECCHI data, such as disentangling, 3D reconstruction, and hydrodynamic modeling of coronal loops, postflare loops, filaments, prominences, and 3D reconstruction of the coronal magnetic field in general.

Authors: Markus J. Aschwanden
Projects: Soho-EIT,Soho-MDI,Soho-CDS,Soho-LASCO,TRACE

Publication Status: Solar Physics, (in press; accepted Feb 17, 2005)
Last Modified: 2005-02-17 12:43
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Astrophysics in 2004 - Section 2: The Sun  

Markus J. Aschwanden   Submitted: 2005-01-17 12:48

(Invited Review, covering publications in Astrophysics and Solar Physics during the year Oct 2003-Sept 2004).

Authors: Trimble,V. and Aschwanden,M.J.
Projects: RHESSI,Soho-EIT,Soho-MDI,Soho-CDS,Soho-LASCO,TRACE

Publication Status: Publications of Astronomical Society of the Pacific (PASP), in press (2005 Jan 15)
Last Modified: 2005-01-17 12:48
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The role of observed MHD oscillations and waves for coronal heating (Invited Review)  

Markus J. Aschwanden   Submitted: 2004-10-01 14:55

In this review we investigate the role of observed coronal wave and oscillation phenomena with respect to the coronal heating problem. A number of wave phenomena have been recently identified with TRACE and SOHO observations, such as standing waves in the fast kink mode and in the slow acoustic mode, as well as propagating acoustic waves, along closed and open magnetic field lines. Most of these wave phenomena have been detected with periods in the order of minutes to half an hour, constrained by the cadence of available imaging instruments. We find that MHD oscillations and waves with acoustic phase speed carry insufficient energy to contribute significantly to coronal heating. However, MHD oscillation and wave phenomena with Alfvénic phase speed carry an energy flux that is comparable with the coronal losses due to radiation and thermal conduction, and thus potentially contribute to the heating of active region loops or postflare loops. Evidence for the presence of propagating Alfvén waves has only been shown indirectly, e.g., by Doppler shift measurements, statistical center-limb effects, and height-dependent scaling laws, but their wave energy flux could acount for the heating of coronal holes.

Authors: Markus J. Aschwanden
Projects: Soho-EIT,TRACE

Publication Status: in Proc. Coronal Heating, SOHO-15 Workshop, held in St.Andrews, UK, ed. ESA, ESTEC Noordwijk, The Netherlands, Special Publicati
Last Modified: 2004-10-01 14:57
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PHYSICS OF THE SOLAR CORONA. AN INTRODUCTION  

Markus J. Aschwanden   Submitted: 2004-09-15 16:45

Chapters: 1. Introduction 2. Thermal Radiation 3. Hydrostatics 4. Hydrodynamics 5. Magnetic Fields 6. Magneto-Hydrodynamics (MHD) 7. MHD Oscillations 8. Propagating MHD Waves 9. Coronal Heating 10. Magnetic Reconnection 11. Particle Acceleration 12. Particle Kinematics 13. Hard X-Rays 14. Gamma Rays 15. Radio Emission 16. Flare Plasma Emission 17. Coronal Mass Ejections (CMEs) - Cover text: Over the past ten years, results from a new generation of solar space missions have become available. Based on those missions and observations made at many wavelengths, from hard X-rays, soft X-rays, extreme UV and radio wavelengths, this book is a comprehensive introduction to solar physics. It describes the solar corona, and sets it in the context of basic plasma physics before moving on to discuss plasma instabilities, plasma heating, magnetic reconnection and particle acceleration processes. The latest results on coronal heating and radiation - fundamental processes in all stars - are presented. Spectacular phenomena, such as solar flares and coronal mass ejections, are described in detail.

Authors: Markus J. Aschwanden
Projects: None,RHESSI,Soho-EIT,Soho-MDI,Soho-CDS,Soho-LASCO,Yohkoh-BCS,Yohkoh-HXT,Yohkoh-SXT,Yohkoh-WBS,TRACE

Publication Status: ISBN: 3-540-22321-5, Praxis Publishing (Chichester, UK) and Springer (Berlin), September 2004
Last Modified: 2004-09-15 16:45
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PULSED PARTICLE INJECTION DURING PETSCHEK-TYPE RECONNECTION IN SOLAR FLARES  

Markus J. Aschwanden   Submitted: 2003-11-11 18:01

The time structure of hard X-ray emission during solar flares shows sub-second pulses which have an energy-dependent timing that is consistent with electron time-of-flight delays. The inferred time-of-flight distances imply an injection height about 50% above the soft X-ray-bright flare loops, where electrons are injected in a synchronized way. No physical injection mechanism is known that can account for the energy synchronization and duration of sub-second pulses. Here we propose a model in terms of dynamic loss-cone angle evolution of newly-reconnected magnetic field lines that relax from the cusp at the reconnection point into a force-free configuration, which can explain the sub-second pulse structure of injected particles as well as the observed correlation between the pulse duration and flare loop size. This quantitative model predicts that the pulse duration of hard X-ray or radio pulses scales with { au}_p approx 2 L_B/v_A (s), which is the Alfvénic transit time through the magnetic diffusion region of a Petschek-type X-point with half length scale LB, and thus provides a direct diagnostic of the magnetic reconnection geometry. It demonstrates also that the observed pulse durations are controlled by the injection time mechanism rather than by the acceleration time scale.

Authors: Markus J. Aschwanden
Projects: RHESSI,Yohkoh-HXT

Publication Status: ApJ, (in press, accepted 2004-Feb-23)
Last Modified: 2004-02-23 13:34
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Solar Magnetic Loops Observed with TRACE and EIT  

Markus J. Aschwanden   Submitted: 2003-11-03 15:39

We select some highlights and new results that have been obtained from detailed ``microscopic'' observations of coronal loop structures with the Transition Region and Coronal Explorer (TRACE) and Extreme Ultraviolet Imager (EIT) instruments, including: (1) the inhomogeneous substructure of EUV loops, (2) the dynamic and non-hydrostatic nature, (3) the non-uniform heating, (4) the magnetic topology at the loop footpoints, (5) the magnetic energy budget for heating, and (6) oscillations and waves in coronal loops.

Authors: Markus J. Aschwanden and Alan M. Title
Projects: Soho-EIT,TRACE

Publication Status: in Stars as Suns: Activity, Evolution and Planets, Symposium S219, IAU 25th Coll. and General Assembly, held in Sydney, Australi
Last Modified: 2003-11-03 15:49
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On the photometric accuracy of RHESSI imaging and spectroscopy  

Markus J. Aschwanden   Submitted: 2003-09-16 08:25

We compare the photometric accuracy of spectra and images in flares observed with the {sl Ramaty High Energy Solar Spectroscopic Imager (RHESSI)} spacecraft. We test the accuracy of the photometry by comparing the photon fluxes obtained in different energy ranges from the spectral-fitting software SPEX with those fluxes contained in the images reconstructed with the {sl Clean, MEM, MEM-Vis, Pixon,} and {sl Forward-fit} algorithms. We quantify also the background fluxes, the fidelity of source geometries, and spatial spectra reconstructed with the five image reconstruction algorithms. We investigate the effects of grid selection, pixel size, field-of-view, and time intervals on the quality of image reconstruction. The detailed parameters and statistics are provided in an accompanying CD-ROM and web page. We find that {sl Forward-fit}, {sl Pixon}, and {sl Clean} have a robust convergence behavior and a photometric accuracy in the order of a few percents, while {sl MEM} does not converge optimally for large degrees of freedom (for large field-of-views and/or small pixel sizes), and {sl MEM-Vis} suffers in the case of time-variable sources. This comparative study documents the current status of the {sl RHESSI} spectral and imaging software, one year after launch.

Authors: Aschwanden,M.J., Metcalf,T.R., Krucker,S., Sato,J., Conway,A., Hurford,G.J., and Schmahl,E.
Projects: RHESSI

Publication Status: Solar Physics (subm., 2003 Sept 15)
Last Modified: 2003-09-16 08:25
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MHD sausage mode oscillations in coronal loops  

Markus J. Aschwanden   Submitted: 2003-09-16 08:21

A recent study by Nakariakov et al. pointed out that the dispersion relation of MHD sausage mode oscillations has been incorrectly applied to coronal loops, neglecting the highly dispersive nature of the phase speed and the long-wavelength cutoff of the wave number. In the light of these new insights we revisit previous observations that have been interpreted in terms of MHD sausage mode oscillations in coronal loops and come to the following conclusions: (1) Fast sausage MHD mode oscillations require such a high electron density imposed by the wave number cutoff that they can only occur in flare loops; (2) In the previously reported radio observations (u approx 100 MHz to 1 GHz) with periods of Papprox 0.5-5 s, the fast sausage MHD mode oscillation is likely to be confined to a small segment (corresponding to a high harmonic node) near the apex of the loop, rather than involving a global oscillation over the entire loop length. The recent microwave and soft X-ray observations of fast periods (Papprox 6-17 s) by Asai et al. and Melnikov et al., however, are consistent with fast sausage MHD oscillations at the fundamental harmonic.

Authors: Aschwanden,M.J., Nakariakov,V.M., and Melnikov,V.F.
Projects: None

Publication Status: ApJ, in press (accepted 2003 Sept 15)
Last Modified: 2003-09-16 08:21
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Observational Tests of Damping by Resonant Absorption in Coronal Loop Oscillations  

Markus J. Aschwanden   Submitted: 2003-06-18 18:31

One of the proposed damping mechanisms of coronal (transverse) loop oscillations in the kink-mode is resonant absorption as a result of the Alfvén speed variation at the outer boundary of coronal loops. Analytical expressions for the period and damping time exist for loop models with thin non-uniform boundaries. They predict a linear dependency of the ratio of the damping time to the period on the thickness of the non-uniform boundary layer. Ruderman and Roberts used a sinusoidal variation of the density in the non-uniform boundary layer and obtained the corresponding analytical expression for the damping time. Here we measure the thickness of the non-uniform layer in oscillating loops for 11 events, by forward-fitting of the cross-sectional density profile n_e(r) and line-of-sight integration to the cross-sectional fluxes F(r) observed with TRACE 171 ang . This way we model the internal ni and external electron density ne of the coronal plasma in oscillating loops. This allows us to test the theoretically predicted damping rates for thin boundaries as function of the density ratio chi = n_e/n_i. Since the observations show that the loops are fully non-uniform we also use numerical results for damping rates to determine the value of chi for the loops. We find that the density ratio predicted by the damping time, {chi}LEDA=0.53pm0.12, is about a factor of 2.5pm2.1 higher than the density ratio estimated from the background fluxes, {chi}=0.30pm 0.16. The lower densities modeled from the background fluxes are likely to be a consequence of the neglected hotter plasma that is not detected with the TRACE 171 ang filter, as well as due to the neglect of the FIP-effect for relative iron enhancement in the oscillating loops. Taking these corrections into account, resonant absorption predicts damping times of kink-mode oscillations that are commensurable with the observed ones and provides a new diagnostic of the density contrast of oscillating loops.

Authors: Markus J. Aschwanden, Richard W. Nightingale, esse Andries, Marcel Goossens, and Tom Van Doorsselaere
Projects:

Publication Status: ApJ, (in press, accepted 2003-Aug-13)
Last Modified: 2003-08-14 07:45
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A new method to constrain the iron abundance from cooling delays in coronal loops  

Markus J. Aschwanden   Submitted: 2003-03-06 18:41

Recent observations with TRACE reveal that the time delay between the appearance of a cooling loop in different EUV temperature filters is proportional to the loop length, Delta t12 propto L. We model this cooling delay in terms of radiative loss and confirm this linear relationship theoretically. We derive an expression that can be used to constrain the coronal iron enhancement α Fe=AFecor/AFePh relative to the photospheric value as function of the cooling delay Delta t12, flux F2, loop width w, and filling factor q_w le 1. With this relation we find upper limits on the iron abundance enhancement of α Fe le 4.8pm 1.7 for 10 small-scale nanoflare loops, and α Fe le 1.4pm 0.4 for 5 large-scale loops, in the temperature range of Tapprox 1.0-1.4 MK. This result supports the previous finding that low-FIP elements, including Fe, are enhanced in the corona. The same relation constitutes also a lower limit for the filling factor, which is q_w ge 0.2pm 0.1 and q_w ge 0.8pm 0.2 for the two groups of coronal loops.

Authors: Aschwanden,M.J., Schrijver,C.J., Winebarger,A.R., and Warren,H.P.
Projects:

Publication Status: ApJ Lett., Vol.588, p. ... (in press, 2003 May 1 issue)
Last Modified: 2003-03-31 09:19
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Astrophysics 2002 (Section 2: Solar Physics)  

Markus J. Aschwanden   Submitted: 2002-12-10 14:44

This excerpt contains an {sl annual increment review} of solar physics papers published in refereed journals during Oct 2001-Sept 2002, totaling to somewhat over 700 publications. During this year we lost the Yohkoh satellite due to a malfunction in Dec 2001, after 10 years of marvelous discoveries, and we saw the successful launch of the {sl Ramaty High Energy Solar Spectroscopic Imager (RHESSI)} on 5 February 2002. Solar physics is reviewed in nine subsections: (1) Solar neutrinos and WIMPs; (2) Seismology inside and behind the Sun; (3) Photosphere; (4) Sunspots; (5) Chromosphere; (6) Corona; (7) Flares and CMEs; (8) Interplanetary meteorology; (9) Solar cycles

Authors: Trimble,V. and Aschwanden,M.J.
Projects:

Publication Status: Publ.Astron.Soc.Pacific, version Dec 2002, to be submitted
Last Modified: 2002-12-10 14:44
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Review of Coronal Oscillations - An Observer's View (INVITED REVIEW)  

Markus J. Aschwanden   Submitted: 2002-10-22 14:13

Recent observations show a variety of oscillation modes in the corona. Early non-imaging observations in radio wavelengths showed a number of fast-period oscillations in the order of seconds, which have been interpreted as fast sausage mode oscillations. TRACE observations from 1998 have for the first time revealed the lateral displacements of fast kink mode oscillations, with periods of approx3-5 minutes, apparently triggered by nearby flares and destabilizing filaments. Recently, SUMER discovered with Doppler shift measurements loop oscillations with longer periods (10-30 minutes) and relatively short damping times in hot flare loops, which seem to correspond to longitudinal slow magnetoacoustic waves. In addition, propagating longitudinal waves have also been detected with EIT and TRACE in the lowest density scale height of loops near sunspots. All these new observations seem to confirm the theoretically predicted oscillation modes and can now be used as a powerful tool for ``coronal seismology'' diagnostic.

Authors: Markus J. Aschwanden
Projects:

Publication Status: in {em Turbulence, Waves, and Instabilities in the Solar Plasma}, NATO Advanced Research Workshops, 16-20 Sept 2
Last Modified: 2002-10-22 14:13
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Tomographic 3D-Modeling of the Solar Corona with FASR  

Markus J. Aschwanden   Submitted: 2002-10-14 10:17

The {sl Frequency-Agile Solar Radiotelescope (FASR)} litteraly opens up a new dimension in addition to the 3D Euclidian geometry: the frequency dimension. The 3D geometry is degenerated to 2D in all images from astronomical telescopes, but the additional frequency dimension allows us to retrieve the missing third dimension by means of physical modeling. We call this type of 3D reconstruction {sl Frequency Tomography}. In this study we simulate a realistic 3D model of an active region, composed of 500 coronal loops with the 3D geometry [x(s),y(s),z(s)] constrained by magnetic field extrapolations and the physical parameters of the density n_e(s) and temperature Te(s) given by hydrostatic solutions. We simulate a series of 20 radio images in a frequency range of u=0.1-10 GHz, anticipating the capabilities of {sl FASR}, and investigate what physical information can be retrieved from such a dataset. We discuss also forward-modeling of the chromospheric and Quiet Sun density and temperature structure, another primary goal of future {sl FASR} science.

Authors: Aschwanden,M.J., Alexander,D., and DeRosa,M.
Projects:

Publication Status: Kluwer ASSL Volume - Solar and Space Weather Radiophysics - eds. D.E.Gary and C.O.Keller, subm (Oct 14, 2002)
Last Modified: 2002-10-14 10:17
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The differential emission measure distribution in the multi-loop corona  

Markus J. Aschwanden   Submitted: 2002-10-02 09:51

This is a rebuttal of a recent Letter on the inadequacy of temperature measurements in the solar corona through narrowband filter and line ratios by Martens et al. We simulate the differential emission measure (DEM) distribution of a multi-loop corona and find that the temperature profile of individual loops can be retrieved with narrowband filter ratios. The apparently flat DEM distributions constructed from CDS line fluxes by Schmelz et al. are an artefact of a smoothing function (in temperature), while the unsmoothed DEM distribution reveals multiple peaks of near-isothermal loops.

Authors: Markus J. Aschwanden
Projects:

Publication Status: The Astrophysical Journal Letter, (accepted Oct 9, 2002), in press)
Last Modified: 2002-10-09 13:37
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Overview of the US System for Post-Docs, Contractors, and Careers in Solar Physics (Invited Review)  

Markus J. Aschwanden   Submitted: 2002-09-27 13:28

This article is intended to offer young physicists specific information on job opportunities and careers in solar physics in the United States (US), a traditional post-Doc country for many young European physicists. About 500 solar physicists life in the United States, which are employed at universities and colleges (43%), in government laboratories (35%), in private companies (8%), or have no official affiliation (14%). We provide a brief overview of the affiliations of the US solar physicists, where the academic institutions are located, what the government laboratories consist of, and what private companies have the largest contracts in the solar physics business. We compile also some demographic and sociological statistics from the larger groups of US astronomers and physicists, that may be of interest to prospective post-Docs.

Authors: Markus J. Aschwanden
Projects:

Publication Status: Proc. 10th European Solar Physics Meeting on Solar Variability: From Core to Outer Frontiers, Special Session Careers of Young E
Last Modified: 2002-09-27 13:28
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Observations and Models of Coronal Loops: From Yohkoh to TRACE (Invited Review)  

Markus J. Aschwanden   Submitted: 2002-07-25 14:58

We review highlights of recent observations of coronal loops in EUV and soft X-rays from {sl Yohkoh} and {sl TRACE}. We review (1) hydrostatic loops, (2) non-hydrostatic loops, (3) oscillating loops, (4) nanoflare loops, and (5) coronal heating, in the light of new observations, with a critical discussion of previous interpretations and theoretical models.

Authors: Markus J. Aschwanden
Projects:

Publication Status: in Proc. Euroconference and IAU Colloquium 188 on Magnetic Coupling of the Solar Atmosphere, 11-15 June 2002, Santorini, Greece,
Last Modified: 2002-07-25 14:58
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Chromospheric height and density measurements in a solar flare observed with RHESSI: II. Data analysis  

Markus J. Aschwanden   Submitted: 2002-07-25 14:48

We present an analysis of hard X-ray imaging observations from one of the first solar flares observed with the {sl Ramaty High Energy Solar Spectroscopic Imager (RHESSI)} spacecraft, launched on 2002-Feb-5. The data were obtained from the 2002-Feb-22, 11:06 UT flare, which occurred close to the northwest limb. Thanks to the high energy resolution of the germanium-cooled hard X-ray detectors on {sl RHESSI} we can measure the flare source positions with a high accuracy as a function of energy. Using a forward-fitting algorithm for image reconstruction, we find a systematic decrease in the altitudes of the source centroids z(varepsilon) as a function of increasing hard X-ray energy varepsilon, as expected in the thick-target bremsstrahlung model of Brown. The altitude of hard X-ray emission as a function of photon energy varepsilon can be characterized by a powerlaw function in the varepsilon=15-50 keV energy range, viz. z(varepsilon ) approx 2.3 (varepsilon / 20 keV)-1.3 Mm. Based on a purely collisional 1-D thick-target model, this height dependence can be inverted into a chromospheric density model n(z), as derived in Paper I, which follows the powerlaw function n_e(z)=1.25 imes 1013 (z/1 Mm)-2.5 cm-3. This density is comparable with models based on optical/UV spectrometry in the chromospheric height range of hlapprox 1000 km, suggesting that the collisional thick-target model is a reasonable first approximation to hard X-ray footpoint sources. At happrox 1000-2500 km, the hard X-ray based density model, however, is more consistent with the {sl ``spicular extended-chromosphere model''} inferred from radio sub-mm observations, than with standard models based on hydrostatic equilibrium. At coronal heights, happrox 2.5-12.4 Mm, the average flare loop density inferred from {sl RHESSI} is comparable with values from hydrodynamic simulations of flare chromospheric evaporation, soft X-ray, and radio-based measurements, but below the upper limits set by filling-factor insensitive iron line pairs.

Authors: Aschwanden,M.J., Brown,J.C., and Kontar,E.P.
Projects:

Publication Status: Solar Physics, (accepted Aug 13), in press.
Last Modified: 2002-08-16 17:25
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Abstracts by Author
Coronal MHD Waves and Oscillations: Observations and Quests (Invited Review)
Particle Acceleration in Solar Flares and Escape into Interplanetary Space
The Sun
2D Feature Recognition and 3D Reconstruction in Solar EUV Images
Astrophysics in 2004 - Section 2: The Sun
The role of observed MHD oscillations and waves for coronal heating (Invited Review)
PHYSICS OF THE SOLAR CORONA. AN INTRODUCTION
PULSED PARTICLE INJECTION DURING PETSCHEK-TYPE RECONNECTION IN SOLAR FLARES
Solar Magnetic Loops Observed with TRACE and EIT
On the photometric accuracy of RHESSI imaging and spectroscopy
MHD sausage mode oscillations in coronal loops
Observational Tests of Damping by Resonant Absorption in Coronal Loop Oscillations
A new method to constrain the iron abundance from cooling delays in coronal loops
Astrophysics 2002 (Section 2: Solar Physics)
Review of Coronal Oscillations - An Observer's View (INVITED REVIEW)
Tomographic 3D-Modeling of the Solar Corona with FASR
The differential emission measure distribution in the multi-loop corona
Overview of the US System for Post-Docs, Contractors, and Careers in Solar Physics (Invited Review)
Observations and Models of Coronal Loops: From Yohkoh to TRACE (Invited Review)
Chromospheric height and density measurements in a solar flare observed with RHESSI: II. Data analysis
Chromospheric Height and Density Measurementsin a Solar Flare Observed with RHESSI: I. Theory
Reconstruction of RHESSI Solar Flare Images with a Forward Fitting Method
Reconciliation of the coronal heating function between Yohkoh and TRACE
PARTICLE ACCELERATION AND KINEMATICS IN SOLAR FLARES. A Synthesis of Recent Observations and Theoretical Concepts (Invited Review)
Analytical Approximations to Hydrostatic Solutionsand Scaling Laws of Coronal Loops
Is the Quiet-Sun Corona Heated by Active Regions or by the Network ?
Nanoflare Statistics from First Principles : Fractal Geometry and Temperature Synthesis
Effects of Temperature Bias on Nanoflare Statistics
Measurement of coronal magnetic twist during loops emergence of NOAA 8069
Evolution of Magnetic Flux Rope in NOAA 9077 Active Region on 14 July 2000
Astrophysics in 2000 (Invited Review)
Transverse Oscillations in Coronal Loops Observed with TRACE: II. Measurements of Geometric and Physical Parameters
Transverse oscillations in coronal loops observed with TRACE: I. An overview of events, movies, and a discussion of common properties and required conditions
Reconciliation of the Coronal Heating Function between Yohkoh and TRACE
Constraining the properties of non-radiative heating of the coronae of cool stars and the Sun
Revisiting the Determination of the Coronal Heating Function from Yohkoh Data
An Evaluation of Coronal Heating Models based on Yohkoh, SoHO, and TRACE Observations
Flare Plasma Cooling from 30 MK down to 1 MK modeled from Yohkoh, GOES, and TRACE observations during the Bastille-Day Event (2000 July 14)
The New Solar Corona (Invited Review)

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