THEMIS Telescope Research Articles

Photoionization Loss of Mercury's Sodium Exosphere: Seasonal Observations by MESSENGER and the THEMIS Telescope.

We present the first investigation and quantification of the photoionization loss process to Mercury's sodium exosphere from spacecraft and ground‐based observations. We analyze plasma and neutral sodium measurements from NASA's MESSENGER spacecraft and the THEMIS telescope. We find that the sodium ion (Na+) content and therefore the significance of photoionization varies with Mercury's orbit around the Sun (i.e., true anomaly angle: TAA). Na+ production is affected by the neutral sodium solar‐radiation acceleration loss process. More Na+ was measured on the inbound leg of Mercury's orbit at 180°–360° TAA because less neutral sodium is lost downtail from radiation acceleration. Calculations using results from observations show that the photoionization loss process removes ∼1024 atoms/s from the sodium exosphere (maxima of 4 × 1024 atoms/s), showing that modeling efforts underestimate this loss process. This is an important result as it shows that photoionization is a significant loss process and larger than loss from radiation acceleration.

Exospheric Na distributions along the Mercury orbit with the THEMIS telescope

The Na exosphere of Mercury is characterized by the variability of the emission lines intensity and of its distribution in time scales from less than one hour to seasonal variations. While the faster variations, accounting for about 10–20% of fluctuations are probably linked to the planetary response to solar wind and Interplanetary Magnetic Field variability, the seasonal variations (up to about 80%) should be explained by complex mechanisms involving different surface release processes, loss, source and migrations of the exospheric Na atoms. Eventually, a Na annual cycle can be identified. In the past, ground-based observations and equatorial density from MESSENGER data have been analyzed. In this study, for a more extensive investigation of the exospheric Na features, we have studied the local time and latitudinal distributions of the exospheric Na column density as a function of the True Anomaly Angle (TAA) of Mercury by means of the extended dataset of images, collected from 2009 to 2013, by the THEMIS solar telescope. Our results show that the THEMIS images, in agreement with previous results, registered a strong general increase in sodium abundance at aphelion and a dawn ward emission predominance with respect to dusk ward and subsolar region between 90° and 150° TAA. This behavior can be explained by desorption of a sodium surface reservoir consisting of sodium that is pushed anti-sunward and condenses preferentially in the coldest regions. Our analyses shows a predominance of subsolar line-of-sight column density along the rest of Mercury's orbit. An unexpected relationship between Northward or Southward peak emission and both TAA and local time is also shown by our analysis. This result seems to contradict previous results obtained from different data sets and it is not easily explained, thus it requires further investigations.

Atmospheric circulation of Venus measured with visible imaging spectroscopy at the THEMIS observatory

Measuring the atmospheric circulation of Venus at different altitudes is important for understanding its complex dynamics, in particular the mechanisms driving super-rotation. Observationally, Doppler imaging spectroscopy is in principle the most reliable way to measure wind speeds of planetary atmospheres because it directly provides the projected speed of atmospheric particles. However, high-resolution imaging spectroscopy is challenging, especially in the visible domain, and most knowledge about atmospheric dynamics has been obtained with the cloud tracking technique. The objective of the present work is to measure the global properties of the atmospheric dynamics of Venus at the altitude of the uppermost clouds, which is probed by reflected solar lines in the visible domain. Our results are based on high-resolution spectroscopic observations with the long-slit spectrometer of the solar telescope THEMIS. We present the first instantaneous “radial-velocity snapshot” of any planet of the solar system in the visible domain, i.e., a complete radial-velocity map of the planet obtained by stacking data on less than 10% of its rotation period. From this, we measured the properties of the zonal and meridional winds, which we unambiguously detect. We identify a wind circulation pattern that significantly differs from previous knowledge about Venus. The zonal wind reveals a “hot spot” structure, featuring about 200 m s−1 at sunrise and 70 m s−1 at noon in the equatorial region. Regarding meridional winds, we detect an equator-to-pole meridional flow peaking at 45 m s−1 at mid-latitudes, i.e., about twice as large as what has been reported so far.

Small-Scale Magnetic Features in the Active Region NOAA 11024

To reveal and study magnetic features in the active region NOAA 11024, temporal changes in the profiles of the Stokes parameter V of photospheric lines Fe I λ 630.15 nm, Fe I λ 630.25 nm, Fe I λ 630.35 nm, and Ti I λ 630.38 nm were analyzed. Data of spectropolarimetric observations carried out with a high temporal and spatial resolution at the French-Italian solar telescope THEMIS (Tenerife Island, Spain) on July 4, 2009, were used. The examined area of the active region includes two pores of opposite polarity and two plages. One of the pores was rapidly developing. For 20 minutes of observations, eruptive processes, such as three Ellerman bombs and chromospheric surges, took place in this area. The V profiles of the photospheric lines substantially differ in different places of the active region. They are normal in most cases. In the pores, their amplitude increases toward outer edges of the pores. The maximum amplitude was noticed in the profiles at the boundary between the emerging pore and the Ellerman bomb. It was rapidly increasing with time. Two small patches with abnormal V profiles of the photospheric lines Fe I λ 630.15 and 630.25 nm have been found. The amplitude of the profiles in these patches was reduced. The amplitude and the shape of the profiles changed with time. One of the patches was between the pores, while the other was in the plage area. During the observations, the polarity of the photospheric magnetic field in these patches changed. Evidence of new, emerging, small-scale magnetic fluxes of opposite polarity was obtained. Due to the emergence of these fluxes, magnetic reconnections started and chromospheric surges and an Ellerman bomb appeared. It has been found that there are strong oscillations in the amplitude of the V profiles of photospheric lines Fe I λ 630.15 and 630.25 nm during Ellerman bombs, which may indicate the pulsed energy realize.

Abnormal Stokes Profiles of the Photospheric Lines in the Region of Chromospheric Dual Flows in the Surroundings of a Solar Pore: 1. Observations

The thermodynamic parameters and parameters of the photospheric magnetic field in the region of chromospheric dual flows in the vicinity of a small pore in the active region NOAA 11024 are presented. The dual chromospheric flows that appeared in the region of abnormal Stokes V profiles of the photospheric lines were associated with the emergence of a new small-scale magnetic flux of positive polarity. Semiempirical photospheric models were obtained by inversion using the SIR program (Stokes Inversion based on Response functions) [42]. Each model contains two components: two thin magnetic flux tubes of different polarity. The magnetic flux has a negative polarity in the first component and positive in the second. The Stokes profiles of the photospheric lines Fe I λ 630.15, 630.25, and 630.35 nm and Ti I λ 630.38 nm from the spectropolarimetric observations with the French–Italian telescope THEMIS (Tenerife, Spain) were used for modeling. The altitudinal dependences of the temperature, line of sight velocity, inclination angle of the magnetic field vector, and azimuth angle in the tubes, as well as the values of the magnetic field strength and macroturbulent velocity, are obtained. The time variations in all parameters of the photosphere are revealed. The new magnetic flux emerged in the region of mixed polarities and was accompanied by the heating of the photosphere and chromosphere. The inferred flux tube models show the temperature enhancement by 400 K in the upper photospheric layers relative to the quiet-Sun model temperature. They indicate a complex, inhomogeneous small-scale structure of the magnetic field and the velocity field. The magnetic field strength in the tubes varies from 0.03 to 0.13 T during the period under consideration. The inclination angles of the magnetic field vector and the azimuth angles strongly differ in magnetic flux tubes and vary in time. The line-of-sight velocity does not exceed 2 km/s. The downflows in the lower layers of the photosphere and the upflows in the upper layers dominate in the first component of the models. In the second component of the model, the material in the upper photosphere is lifted. The macroturbulent velocity in most cases exceeds its value for the unperturbed photosphere. The velocity is greater in the second component of the models. The emergence of the new magnetic flux could lead to the magnetic reconnection and occurrence of a microflare.

MAGNETIC FIELD IN ATYPICAL PROMINENCE STRUCTURES: BUBBLE, TORNADO, AND ERUPTION

ABSTRACT Spectropolarimetric observations of prominences have been obtained with the THEMIS telescope during four years of coordinated campaigns. Our aim is now to understand the conditions of the cool plasma and magnetism in “atypical” prominences, namely when the measured inclination of the magnetic field departs, to some extent, from the predominantly horizontal field found in “typical” prominences. What is the role of the magnetic field in these prominence types? Are plasma dynamics more important in these cases than the magnetic support? We focus our study on three types of “atypical” prominences (tornadoes, bubbles, and jet-like prominence eruptions) that have all been observed by THEMIS in the He i D3 line, from which the Stokes parameters can be derived. The magnetic field strength, inclination, and azimuth in each pixel are obtained by using the inversion method of principal component analysis on a model of single scattering in the presence of the Hanle effect. The magnetic field in tornadoes is found to be more or less horizontal, whereas for the eruptive prominence it is mostly vertical. We estimate a tendency toward higher values of magnetic field strength inside the bubbles than outside in the surrounding prominence. In all of the models in our database, only one magnetic field orientation is considered for each pixel. While sufficient for most of the main prominence body, this assumption appears to be oversimplified in atypical prominence structures. We should consider these observations as the result of superposition of multiple magnetic fields, possibly even with a turbulent field component.

Spectropolarimetric investigation of an Ellerman bomb: 2. Photospheric models

Semiempirical models of the photosphere of an Ellerman bomb in the NOAA 11024 active region were obtained using profiles of Stokes parameters I, Q, U, and V of photospheric lines. Spectropolarimetric observations were conducted using the French–Italian THEMIS telescope (Tenerife, Spain). The SIR inversion code [28] was used in the modeling. The models have two components: a magnetic flux tube and nonmagnetic surroundings. The dependences of temperature, magnetic field strength, inclination of the magnetic field vector, and line-of-sight velocity in the tube on the optical depth were obtained. The models demonstrate that the thermodynamic parameters of the Ellerman bomb photosphere differ considerably from those of the quiet photosphere. The temperature in the tube model varied nonmonotonically with height and deviated by up to 700–900 K from its values for the quiet photosphere. Downflows were observed in the lower and the upper photospheric layers. The line-of-sight velocity in the upper layers of the photosphere was as high as 17 km/s. The magnetic field strength in the models varied from 0.1–0.13 T in the lower photospheric layers to 0.04–0.07 T in the upper ones. The physical state of the photosphere did change in the course of observations.

Spectral study of a pair of Ellerman bombs

Results of the analysis of spectral observations of two Ellerman bombs in the Hα line are presented. These bombs (EB-1 and EB-2) appeared and evolved in the active region NOAA 11024 in the emerging magnetic flux area. The spectral data of a high temporal and spatial resolution were obtained with the French–Italian solar telescope THEMIS (Tenerife Island, Spain; THEMIS stands for Telescope Heliographique pour l’Etude du Magnetisme et des Instabilites Solaires) on July 4, 2009. The Hα-line profiles obtained for different periods of the Ellerman bombs (EBs) evolution were asymmetrical, demonstrating the emission excess in the long-wavelength wing. The intensity variations in the line wings indicate both the gradual and pulsed release of energy in the course of EBs. Temporal variations in the line-of-sight velocities Vlos of the chromospheric material at a level of the Hα-core formation showed two periods in the velocity enhancement, containing several individual peaks. The maximum line-of-sight velocity of the material was–9 and 8 km/s toward and from the observer, respectively. Rapid upward and downward plasma streams (where Vlos reaches–80 and 50 km/s, respectively) were sometimes observed. The Ellerman bombs were accompanied by small chromospheric ejections (surges) lasting for 0.5–1.5 min. A fine structure of EBs was found in the Hα-line spectra obtained during 4 min, when the intensity in the line wings sharply increased. The peculiarities of variations in the intensity of the Hα-line wings and the line-of-sight velocity of the chromospheric material suggest that two investigated EBs appeared and evolved as a physically connected pair. Our results support the model wherein the magnetic reconnection in the lower atmospheric layers is considered as a triggering mechanism for the EB formation.

STRUCTURE OF PROMINENCE LEGS: PLASMA AND MAGNETIC FIELD

ABSTRACT We investigate the properties of a “solar tornado” observed on 2014 July 15, and aim to link the behavior of the plasma to the internal magnetic field structure of the associated prominence. We made multi-wavelength observations with high spatial resolution and high cadence using SDO/AIA, the Interface Region Imaging Spectrograph (IRIS) spectrograph, and the Hinode/Solar Optical Telescope (SOT) instrument. Along with spectropolarimetry provided by the Télescope Héliographique pour l’Etude du Magnétisme et des Instabilités Solaires telescope we have coverage of both optically thick emission lines and magnetic field information. AIA reveals that the two legs of the prominence are strongly absorbing structures which look like they are rotating, or oscillating in the plane of the sky. The two prominence legs, which are both very bright in Ca ii (SOT), are not visible in the IRIS Mg ii slit-jaw images. This is explained by the large optical thickness of the structures in Mg ii, which leads to reversed profiles, and hence to lower integrated intensities at these locations than in the surroundings. Using lines formed at temperatures lower than 1 MK, we measure relatively low Doppler shifts on the order of ±10 km s−1 in the tornado-like structure. Between the two legs we see loops in Mg ii, with material flowing from one leg to the other, as well as counterstreaming. It is difficult to interpret our data as showing two rotating, vertical structures that are unrelated to the loops. This kind of “tornado” scenario does not fit with our observations. The magnetic field in the two legs of the prominence is found to be preferentially horizontal.

Spectropolarimetric investigation of an Ellerman bomb: 1. Observations

Spectra of an Ellerman bomb in the NOAA 11024 active region were obtained in spectropolarimetric observations with the French–Italian THEMIS telescope (Tenerife, Spain). The variations of profiles of the Stokes parameters I, Q, U, and V of photospheric lines were analyzed. The chosen lines had different intensities and magnetic-field sensitivities. It was found that the photospheric line profiles in the Ellerman bomb spectra differed greatly from the profiles for the quiet photosphere outside the active region. The Stokes I profiles of photospheric lines in the Ellerman bomb spectra were much weaker. The largest values of the Stokes parameters Q, U, and V were derived for the Fe I λ 630.25 nm magnetosensitive line. The Stokes parameter V was the highest in the central region of the Ellerman bomb, while the maximum Q and U parameters were observed at one of the edges of the Ellerman bomb. It follows from the comparison of the Stokes parameters for the Ellerman bomb and microflares that the Q, U, and V parameters for the bomb are much higher than those for flares.

Cancellation analysis of current density in solar active region NOAA10019

Solar flares are often associated with changes in the fine magnetic structure of the emitting active region. Such topological modification results in variations of both the scaling properties of the fields’ fluctuations, and the fractal dimension of the associated gradients. The use of cancellation analysis of the current density has been attempted for the identification and quantitative estimation of such changes. The characteristics of the magnetic vector as measured by THEMIS telescope for the active region NOAA10019 have been studied in this paper, suggesting the presence of disrupted current filaments. The variation of the fractal dimension of the current structures, and in particular their smoothing, is discussed in relationship with occurrence of one flare in the active region.

The chromospheric line-of-sight velocity variations in a solar microflare

The variations of the chromospheric line-of-sight velocity in the active region NOAA 11024 are studied before, during, and after a solar microflare on 2009 July 4. At the day of the observations the main emergence phase was in this active region. The new emerging flux has interacted with the pre-existing magnetic field.The spectropolarimetric observations were carried out with the French–Italian THEMIS telescope (Spain, Tenerife). We used Hα spectra of the high resolution obtained over 21min. The spatial resolution was ∼1 arcsec. The time interval between the spectra was 2.84s. Doppler velocities were measured in the microflare location and its surroundings. We have revealed strong temporal variations of the line-of-sight velocity in the chromosphere. The velocities changed in the range −33–10km/s. We revealed the velocity oscillations with the amplitude of 4–5km/s. 12–14min before the microflare both upward and downward motions with velocity values reaching about 20km/s are found on the outer edge of the region studied. The amplitude of the oscillations increased. It may be the signature of the magnetic reconnection.

Proper horizontal photospheric flows in a filament channel

Context. An extended filament in the central part of the active region NOAA 11106 crossed the central meridian on Sept. 17, 2010 in the southern hemisphere. It has been observed in Hα with the THEMIS telescope in the Canary Islands and in 304 Å with the EUV imager (AIA) onboard the Solar Dynamic Observatory (SDO). Counterstreaming along the Hα threads and bright moving blobs (jets) along the 304 Å filament channel were observed during 10 h before the filament erupted at 17:03 UT.

Horizontal or vertical magnetic fields on the quiet Sun

Different analyses of identical Hinode SOT/SP data of quiet-sun magnetic fields have in the past led to contradictory answers to the question of whether the angular distribution of field vectors is preferentially horizontal or vertical. These answers have been obtained by combining the measured circular and linear polarizations in different ways to derive the field inclinations. A problem with these combinations is that the circular and linear polarizations scale with field strength in profoundly different ways. Here, we avoid these problems by using an entirely different approach that is based exclusively on the fundamental symmetry properties of the transverse Zeeman effect for observations away from the disk center without any dependence on the circular polarization. Systematic errors are suppressed by the application of a doubly differential technique with the 5247-5250 \AA\ line pair for observations with the ZIMPOL-2 imaging polarimeter on the French THEMIS telescope on Tenerife. This allows us to determine in a model- and resolution-independent way how the angular distribution of the intranetwork magnetic fields changes from being preferentially vertical in the lower and middle photosphere to become preferentially horizontal in the upper photosphere.

Atmosphere Dynamics of the Active Region NOAA 11024

We present results of the study of chromospheric and photospheric line-of-sight velocity fields in the young active region NOAA 11024. Multi-layer, multi-wavelength observational data were used for the analysis of the emerging flux in this active region. Spectropolarimetric observations were carried out with the telescope THEMIS on Tenerife (Canary Islands) on 4 July 2009. In addition, space-borne data from SOHO/MDI, STEREO and GOES were also considered. The combination of data from ground- and space-based telescopes allowed us to study the dynamics of the lower atmosphere of the active region with high spatial, spectral, and temporal resolutions. THEMIS spectra show strong temporal variations of the velocity in the chromosphere and photosphere for different activity features: two pores, active and quiet plage regions, and two surges. The range of variations of the chromospheric line-of-sight velocity at the heights of formation of the H-alpha core was extremely large. Both upward and downward motions were observed in these layers. In particular, a surge with upward velocities up to -73 km/s were detected. In the photosphere, predominantly upward motions were found, varying from -3.1 km/s upflows to 1.4 km/s downflows in different structures. The velocity variations at different levels in the lower atmosphere are compatible with magnetic flux emergence.

Hanle diagnostics of weak solar magnetic fields:

Context. The quiet Sun magnetism has been intensively investigated in recent years by various observational techniques. But several issues, such as the question of the isotropy and of the energy density spectrum of the mixed polarity turbulent magnetic fields, are still under debate. Aims. Here we present an inversion method that allows us to constrain the depth-dependence of the magnetic field strength. We use the center-to-limb variations of linear scattering polarization measured in molecular lines of C2 and MgH molecules with different sensitivities to the Hanle effect. We consider six C2-triplets and one MgH line in the spectral range between 515.7 nm and 516.1 nm observed with the THEMIS Telescope. Methods. One of the delicate problems with Hanle diagnostics is to disentangle the effects of elastic depolarizing collisions from the depolarization due to the Hanle effect of the magnetic field. By making use of the different sensitivities of the molecular lines in our spectral range to microturbulent magnetic fields and, by using a non-LTE radiative transfer modeling of the line formation, we are able to determine both the depolarizing collision cross-section and the magnetic strength. We use a standard 1D quiet Sun atmospheric model and we invert the full set of center-to-limb polarization rates measured at line centers, with a depth-dependent magnetic field described by three free parameters. The depolarizing collision cross-section is also treated as a free parameter. A downhill simplex method is used to find the best-fitting values for the collisional and magnetic strength parameters. Results. For the elastic depolarizing collisions cross-section for the C2 lines we obtain α (2) = 1.6 ± 0.4 × 10 −9 cm 3 s −1 , which is within an order of magnitude of the value previously obtained for MgH lines from a differential Hanle effect analysis. The observational constraints provided by the MgH and C2 line polarization give access to the altitude range between z = 200 km and z = 400 km above the base of the photosphere. We find that the turbulent magnetic field strength decreases from 95 Gauss at the altitude z = 200 km to 5 Gauss at z = 400 km. Conclusions. The turbulent magnetic field strength that we derive from the Hanle effect shows a strong vertical gradient in the upper photosphere. We point out that this behavior may explain why very different turbulent magnetic field strengths have been inferred from the interpretation of Hanle depolarization when using different lines formed at different altitudes. We notice that the presence of a strong depth gradient is not compatible with the assumption of isotropy of the turbulent field.

The quiet Sun magnetic field: statistical description from THEMIS observations

Context. The pioneer interpretation of Hanle-effect depolarization observed at the limb was the one of a turbulent nature for the solar internetwork photospheric magnetic field. In the present paper, we propose an alternative interpretation of these measurements, which are now complemented with Zeeman-effect observations to allow one to conclude on the properties of weak fields. Aims. In a previous paper, we presented an internetwork field diagnostic from data obtained with the ZIMPOL II polarimeter mounted on the THEMIS telescope. In the present paper, we present the results obtained with the THEMIS polarimeter with ten times more pixels. The agreement between the results obtained with the two polarimeters confirm the goodness of both the THEMIS polarimeter measurements and our data treatment. Methods. The Zeeman-effect measurements are interpreted via a 2-component model, which has a field-free component and a magnetized one, filling a fraction of the analyzed pixel equal to 1 − α and α, respectively. We determine this α parameter independently of the magnetic inversion. We already applied these methods to the previous interpretation of the ZIMPOL/THEMIS data. Results. The magnetic field strength and magnetic field inclination are not independent, because the strongest fields are more vertical and the weakest fields are more horizontal, both in ZIMPOL/THEMIS and THEMIS/THEMIS data. Conclusions. This suggests that the photospheric internetwork field has the structure of scattered narrow fluxtubes consisting in a vertical field, which weakens in opening – widening with individual field line bending – with height. The weakest fields then have a 2D horizontal structure, instead of the usually admitted 3D turbulent one. This does not contradict the previous Hanle-effect observations, because it is insensitive to vertical fields. The number of fluxtubes inside each pixel (which was 0.21 arcsec for the THEMIS/THEMIS and 0.53 arcsec for the ZIMPOL/THEMIS data) should, however, remain small. We could make a conclusion about this after observing a non-zero spatial correlation of the magnetic field orientation, with an estimated correlation length of 250 km.

Detecting photons with orbital angular momentum in extended astronomical objects: application to solar observations

Context. The orbital angular momentum (OAM) of the photon is a property of light from astronomical objects that has not yet been measured. We propose a method of measuring the OAM spectrum of light from an extended natural source, the Sun. Relating the OAM spectrum of different solar areas to its structures could lead to a novel remote sensing technique.Aims. We present a method for measuring the OAM spectrum of solar photons.Methods. The THEMIS telescope is being used with a novel phase-diversity technique. A spatial light modulator is placed on one pupil image, and an ad-hoc optical setup allows the measurement of two simultaneous phase-diverse images in the same CCD, with equal optical paths.Results. Preliminary results show that very good seeing is mandatory for this kind of observation. The method works in the laboratory, and good seeing conditions in the 2010 campaign are being awaited.

Vector magnetic field and vector current density in and around the δ-spot NOAA 10808

AbstractThe context is that of the so-called “fundamental ambiguity” (also azimuth ambiguity, or 180° ambiguity) in magnetic field vector measurements: two field vectors symmetrical with respect to the line-of-sight have the same polarimetric signature, so that they cannot be discriminated. We propose a method to solve this ambiguity by applying the “simulated annealing” algorithm to the minimization of the field divergence, added to the longitudinal current absolute value, the line-of-sight derivative of the magnetic field being inferred by the interpretation of the Zeeman effect observed by spectropolarimetry in two lines formed at different depths. We find that the line pair Fe I λ 6301.5 and Fe I λ 6302.5 is appropriate for this purpose. We treat the example case of the δ-spot of NOAA 10808 observed on 13 September 2005 between 14:25 and 15:25 UT with the THEMIS telescope. Besides the magnetic field resolved map, the electric current density vector map is also obtained. A strong horizontal current density flow is found surrounding each spot inside its penumbra, associated to a non-zero Lorentz force centripetal with respect to the spot center (i.e., oriented towards the spot center). The current wrapping direction is found to depend on the spot polarity: clockwise for the positive polarity, counterclockwise for the negative one. This analysis is made possible thanks to the UNNOFIT2 Milne-Eddington inversion code, where the usual theory is generalized to the case of a line (Fe I λ 6301.5) that is not a normal Zeeman triplet line (like Fe I λ 6302.5).

Synthetic analysis of a two-ribbon microflare

High-resolution Stokes spectral data of Hα, Ca II 8542 Å, and Fe 16302.5 Å lines for a two-ribbon microflare (TRMF) were simultaneously obtained by the THEMIS telescope on 2002 September 5. We derive the intensity, velocity, and longitudinal magnetic field maps. The hard X-ray emission observed by RHESSI provides evidence of nonthermal particle acceleration in the TRMF. Using Hα and Ca II 8542 Å line profiles and a non-LTE calculation, we obtain semi-empirical atmospheric models for the two brightest kernels of the TRMF. Our result indicates that the temperature enhancement in the chromosphere is more than 2500 K. The kinetic and radiative energies at the kernels are also estimated, resulting in an estimate of the total energy of the TRMF of about 2.4 ×1029 erg. Observations indicate that the TRMF results from the low coronal magnetic reconnection following the eruption of a small filament. However, the local temperature “bump" in the chromosphere presents a puzzle for such a standard flare model. A possible solution to this is discussed.