Pdf/47/aa5688-06.pdf.urlA&A 460, 597–604 (2006) Transition region counterpart of a moving magnetic feature
C.-H. Lin1,2,3, D. Banerjee4, E. O'Shea1, and J. G. Doyle1 1 Armagh Observatory, College Hill, Armagh BT61 9DG, North Ireland, UK e-mail: firstname.lastname@example.org 2 National Center for Theoretical Sciences, Physics division, National Tsing-Hua University, Hsinchu, Taiwan3 Astronomy Department, Yale University, New Haven, CT06511, USA4 Indian Institute of Astrophysics, Koramangala, Bangalore 560034, India Received 24 May 2006 / Accepted 30 August 2006 Context. While moving magnetic features have been studied extensively at the photospheric level, the eﬀect they have on the upperatmosphere remains largely unknown, and it is this which we seek to address in this work.
Aims. In this work we aim to investigate the chromospheric and transition-region dynamics associated with a moving magneticmonopole by using spectral time-series and images.
Methods. Cross correlation was applied to images taken by diﬀerent instruments and at diﬀerent times in order to spatially correlatebrightenings seen at transition region temperatures with moving magnetic features seen in magnetograms. We used wavelet analysisto examine and compare the periodicities of time-series signals in diﬀerent regions.
Results. Oscillations with a multitude of frequencies are found in the chromospheric and transition-region brightenings associatedwith a moving magnetic monopole. The region of the brightenings shows a tendency to be blue-shifted when compared to the averagemotion of the entire field of view. The results indicate the presence of waves and/or flows carrying energy from the monopole to thehigher atmosphere.
Conclusions. We studied the influence of a moving magnetic monopole, as recorded by magnetograms, up to transition regiontemperatures. This suggests that the magnetic monopole, despite being small, can influence dynamics in the upper atmospheric layers.
Key words. Sun: granulation – Sun: magnetic fields – Sun: oscillations – Sun: chromosphere – Sun: transition region
field lines in a small part of the canopy dip down to produce aU-loop. To date, all the studies of MMFs have focused on the More than 35 years ago, Sheeley (1969) discovered, in spectro- properties of the feature. An extensive statistical study of all heliograms at λ = 3883 Å, a steady flow of bright points mov- the properties of MMFs was recently carried out by Hagenaar ing outward from a sunspot. These moving bright points were & Shine (2005) using the high-resolution Michelson Doppler later seen in the magnetograms by Harvey & Harvey (1973), Imager (MDI) magnetograms and the white-light images of MDI who named the features as moving magnetic features (MMFs).
and TRACE (Transition Region and Coronal Explorer). In this The authors suggested that the features were magnetic knots re- paper, we will look at a diﬀerent aspect of MMFs, that is, their sulting from the interactions between the sunspot magnetic field eﬀect on the higher atmosphere. We detected wave propagation and the mass motion of supergranules. MMFs are very small and an indication of energy deposit in the transition zone, at the (<1500 km), and can be either bipolar or unipolar. They often location above a unipolar MMF. Our analysis shows that the phe- emerge near the outer edge of a penumbra, and move radially nomena in the transition region are spatially and temporally cor- outward through an area with weak line-of-sight magnetic fields.
related to the existence of the MMF, suggesting that the MMF, However, magnetic features migrating inward to the umbra have despite being small, is capable of influencing the dynamic be- also been observed (Ravindra et al. 2004). Zhang et al. (1992) haviour in the atmosphere at least up to the transition region.
reported that unipolar MMFs carry net flux from the sunspotwhile bipolar MMFs do not. Earlier observations by Lee (1992) 2. Observation and data calibration
found that the orientation of MMFs is random with no correla-tion with the polarity of the sunspot. The result was in agree- We utilized time series from the Normal Incidence Spectrometer ment with the scenario of detached flux tubes, first suggested (NIS) of CDS/SoHO, images from MDI/SoHO, TRACE, EIT by Harvey & Harvey (1973); i.e., a flux tube perturbed by the (Extreme ultraviolet Imaging Telescope), and raster images from outward supergranulation flow is detached from the umbra, and NIS/CDS to study oscillatory behaviour in the transition region floats to the surface while being pulled outward by the flow. The above a moving magnetic monopole. The time series correspond twists and the kinks of the tube then appear as the randomly to the dataset s29536r00. It was a 95-min time-series observation oriented small magnetic features moving away from the umbra.
taken on 2004 Feb. 13 at 07:59–09:35 UT. During the observa- However, more recent studies by Yurchyshyn et al. (2001) and tion, the pointing of the detector was fixed in space while the Zhang et al. (2003) found that the leading pole in a bipolar MMF Sun rotated under the field of view (FOV). The exposure time is often has the same polarity as the sunspot. Based on their results, 30 s, and the cadence is approximately 37 s. The details of the the authors suggested that MMFs are formed when the sunspot diﬀerent image observations are listed in Table 1.
C.-H. Lin et al.: Transition region counterpart of a moving magnetic feature Table 1. The details of the image observations.
Wavelength (Spectral line) Covered time period 2004-Feb.-13 06:00–08:30 UT 2004-Feb.-13 13:53–13:59 UT 2004-Feb.-13 08:30 UT 2004-Feb.-13 13:40 UT 2004-Feb.-13 07:13 UT NIS/CDS (s29535r00) 2004-Feb.-13 07:37–07:59 UT NIS/CDS (s29535r00) 2004-Feb.-13 07:37–07:59 UT NIS/CDS (s29537r00) 2004-Feb.-13 14:24–14:46 UT NIS/CDS (s29537r00) 2004-Feb.-13 14:24–14:46 UT NIS/CDS data were calibrated by the most up-to-date stan- oscillations without being divided by the trend are called abso- dard calibration routines in SolarSoft1, with the oﬀset be- tween NIS1 and NIS2 corrected using the routine nis rotate.
The properties of the oscillations (e.g.periods, amplitudes, As explained in CDS Software Note No. 532, NIS/CDS line etc.) were determined by the use of wavelet transforms. A profiles were broadened after SoHO's recovery in October wavelet transform, being capable of revealing the temporal de- 1998. Therefore, each spectral line was fitted with a broadened pendence of a signal, is more suitable than the traditional Fourier Gaussian (BGauss) function, and the line intensity was com- transform to analyze the oscillations that vary over time. The puted accordingly. The NIS raster images and time series of in- wavelet we used is the standard Morlet wavelet. To determine dividual lines were then constructed from the line intensity. The whether or not the oscillations are above the noise level, we im- errors in the line intensities were computed based on the equa- plemented a randomization method (Linnell Nemec & Nemec tions in CDS Software Note No. 49.
1985) to estimate the significance level of the peaks in the The noise and cosmic ray contamination in the TRACE im- wavelet spectrum. Details on the wavelet analysis may be found ages were reduced by a number of de-spike, de-streak, and in Torrence & Compo (1998) and O'Shea et al. (2001).
smoothing routines. The orientations of the EIT and MDI im- When a signal is composed of multiple oscillations with very ages and the NIS raster images were corrected for the eﬀect of diﬀerent intensities, the weaker ones will be obscured by the the SoHO instruments being turned 180◦ during our observation.
stronger ones. To reveal these weaker components of the sig- After all the maps are calibrated, the coordinate diﬀerence be- nal, we filtered out the stronger modes by removing the corre- tween maps from the same instrument was corrected by the func- sponding wavelet scales. In this paper, we applied two filters, tion coreg map, and the coordinate diﬀerence between maps P700 and P300, which filter out periods longer than 700 s and from diﬀerent instruments was determined from a cross correla- 300 s, respectively. The filtered signals are called P700-filtered tion between maps corresponding to a similar temperature. Due and P300-filtered. We also tried out other filters, but the result- to the limited resolution of NIS/CDS maps, the uncertainty of ing power was not significant enough. To infer the motion of the coordinate determination in this work is approximately 7.
material, we computed the relative Doppler velocity (vd ) at each To be consistent, all the maps shown in this paper were shifted to pixel i as follows: 07:59 UT, which is the starting time of the NIS/CDS time-seriesobservation s29536r00.
vd = c × (λ i − λav)/λav, where c is the speed of light, λi is the wavelength at pixel i, and 3. Time-series analysis
av is the average wavelength of the data set. Hence, vd repre- sents the motion of a point relative to the average motion of the The oscillations were extracted from the time-series signals by area covered by the observation, and does not necessarily reflect subtracting the trend from the intensity variation. The process the absolute velocity of the material at the location.
is called de-trending. The slit width of our NIS/CDS detector is4. Based on the solar rotation rate at the pointing of the de-tector, a feature would cross the slit in 25 min. Hence, an os- 4. Results
cillation source of size ≈4 with periods longer than 12.5 min 4.1. Signatures of the MMF at different temperatures would leave our FOV before the second cycle is complete, andcannot be identified with confidence. Therefore, the trend of our The region of our observation is active region AR0554. A repre- time-series data is computed by a 25-pt running average to re- sentative magnetogram of the region is shown in Fig. 1. The two move the periodicities of 15 min and longer. The amplitudes of white contours illustrate the umbra and penumbra. The sunspot an oscillation can be aﬀected by the intensity of a spectral line.
can be seen surrounded by a ring devoid of strong magnetic In other words, the amplitudes in a bright region can be greater fields along the line of sight, which can also be seen in Fig. 2.
than in a dark region simply because of the diﬀerence in the pho- Within this ring, there are several small magnetic elements. From ton numbers the detector received in the two regions. To reduce the series of magnetograms, we found that these elements are the amplitude diﬀerence due to the line intensity and to prevent very dynamic. Here, we will examine one of the elements, which the oscillations in the dark region being obscured by the oscilla- crossed the field of view (FOV) of our sit-and-stare observation.
tions in the bright region, we divided the oscillations by the trend This magnetic element has a positive magnetic polarity, pre- to produce what are called relative oscillations. In contrast, the sumably a monopole. It was moving away from the sunspot ofnegative polarity throughout the time period, 06:00–08:30 UT (cf. Fig. 2), and had disappeared in the second time series, 13:53–13:59 UT. To examine the influence of the magnetic C.-H. Lin et al.: Transition region counterpart of a moving magnetic feature Fig. 1. A MDI magnetogram showing the magnetic configuration of ac-
tive region AR0554. The sunspot is marked by the white contours.
monopole on the higher atmosphere, we show images formedat diﬀerent temperatures in Fig. 3. Interestingly, a bright patchlocated at ≈(–30, 2) was seen in the NIS/CDS He i 522.2 Å and O v 629.7 Å raster images at 07:37–07:59 UT and in the Fig. 2. MDI magnetograms taken at 06:00, 06:24, 06:59, 07:30, 08:00,
EIT He ii 304 Å image at 07:19 UT (the region in the white and 08:30 UT, as indicated above each respective image. All the images square in Fig. 3). Although the bright patch is not exactly at the have been shifted to the location corresponding to 07:59 UT, which is coordinate of the monopole, the diﬀerence is within the reso- the observation starting time of the NIS/CDS time series s29536r00. In lution of NIS/CDS maps. In addition to the spatial correlation, other words, the eﬀect of solar rotation is removed. The area covered by the bright patch had disappeared in the later raster images at this time-series observation is bounded between the two vertical lines.
14:24–14:46 UT, when the monopole also disappeared from the The white spot enclosed by the white square is the moving magnetic MDI magnetograms. Such coincidence in time indicates a pos- monopole discussed in this paper. The figure shows that this MMF wasat approximately (−29, 4) at 06:00 UT and moved to approximately sible connection between the existence of the moving magnetic (−32, 8) at 08:30 UT.
element and the existence of the bright patch despite the absenceof MDI data between 08:30 and 13:53 UT. In addition, we de-tected significant oscillations at the brightening location in thetime series of He i 522.2 Å and O v 629.7 Å. The oscillations 4.2. The detected indication of waves will be discussed in Sect. 4.2.1.
To extract and examine the periodic features in the time series, In Fig. 4, the contours of the magnetograms at diﬀerent we applied the de-trend procedure to remove the spatial eﬀect. In times are plotted over the TRACE 1600 Å channel map taken addition, we calculated the relative Doppler velocity to examine at 08:30 UT. The two vertical dashed lines denote the begin- the material motion in the MMF relative to the average motion ning and end locations of the NIS time-series observations. The of the entire FOV of the time series. The results are shown in small circular contours traced by the two "L" shapes (from Solar Fig. 6. The location corresponding to the brightening seen in X ≈ −33 to −29 and Solar Y ≈ 2 to 7) correspond to the the NIS/CDS raster image and the MMF seen in MDI magne- positions of the moving magnetic monopole at diﬀerent times.
tograms (cf. Fig. 3) is enclosed in the white box, which cov- Therefore, the monopole moved ≈4 in the X direction and ≈5 ers Solar Y = 0–13 and a 25-min observation duration from in the Y direction over the time period of 2.5 h, which infers 08:35 UT to 09:00 UT. Based on the solar rotation rate at the an apparent moving speed of ≈0.5 km s−1(1 = 715 km). The location, a 25-min duration is equivalent to a distance of approx- speed, direction of motion and the proximity to the sunspot al- imately 4 in the Solar X direction.
low us to identify this monopole as a moving magnetic feature.
In the intensity time-series (the top panel), we can see a The locations of this MMF at diﬀerent times show that strong brightening in the area marked by the white box. The the MMF appears to move along the boundary of the super- MMF contours in Fig. 3 show that this monopole is ≈4 across in granulation cell located at Solar X ≈ −50 to −25, Solar the Solar X direction and that its location in Solar Y at 08:30 UT Y ≈ 0 to 20. Comparing this TRACE 1600 Å channel map is ≈7–10. Hence, this strong emission seen in the white box with another map taken at a later time (cf. Fig. 5), we can see is likely correlated with the MMF within our spatial resolution.
that this cell was broken by 13:40 UT, when the monopole also After the trend is subtracted from the time series, a periodic pat- tern can be seen in the white box (cf. second panel in Fig. 6).
C.-H. Lin et al.: Transition region counterpart of a moving magnetic feature Fig. 4. The TRACE 1600 Å channel image taken at 08:30 UT. The over-
plotted contours are the MDI magnetograms taken at 06:00 UT (white),
06:24 UT (orange), 06:59 UT (black), 07:30 UT (red), 08:00 UT (yel-
low) and 08:30 UT (blue). All the images have been shifted to the
location corresponding to 07:59 UT, which is the observation starting
time of the time series, NIS s29536r00. The area covered by this time-
series observation is bounded between the two vertical dashed lines.
The thread of circular contours spreading from Solar X ≈ −33 to −29
and Solar Y ≈ 2 to 11, as traced by the two "L" shapes, represents the
locations of the moving magnetic monopole from 06:00–08:30 UT. The
thread coincides with the boundary of a super-granulation cell (see also
the white-square enclosed region in Fig. 5).
However, this pattern, consisting of only two cycles, may be amanifestation of spatial eﬀects rather than a periodic signal. Theexamination of the possible temporal periodicity is discussedin Sect. 4.2.1. From the relative Doppler velocity (the bottompanel), a clear stripe of blue-shifts between 10 and −5 can beseen during almost the entire observation period. Specifically,in the region of the white box, the blue shifts are localized be-tween 7 and 0. We further examined the relative velocity atindividual pixels. The results of the examination are discussedin Sect. 4.2.2.
4.2.1. Oscillations We applied the wavelet analysis to examine the behaviour of theNIS/CDS O v and He i time series over the moving magnetic Fig. 3. The maps of NIS O v 629.7 Å taken at 07:37 UT (top), EIT
monopole. From Fig. 3, we see that the region of interest ex- He ii 304 Å at 07:19 UT (middle), and NIS He i 522.2 Å at 07:37 UT (bottom). The MDI magnetograms taken at 06:59 UT (green), 07:30 UT tends from Solar Y ≈ −4 to 10, i.e.the upper and lower edge (red), 08:00 UT (yellow) and 08:30 UT (blue) are over-plotted on all of the white square. In Fig. 7, we use the results of the pixel three maps to illustrate the variation of the magnetic fields, and, specifi- at Solar Y ≈ 3 (corresponding to pixel 20 of our CDS slit) to cally, the motion of the MMF. All the maps were shifted to the location illustrate the common properties seen in the oscillations of the corresponding to 07:59 UT, which is the observation starting time of the bright patch of O v. We would like to point out that the adjacent NIS/CDS time series s29536r00. The area covered by this time-series pixels also show similar oscillation pattern, whereas pixels 18, observation is bounded between the two vertical lines. The white square 19, 21, and 22 (≈ −5, −1, 7 and 11) show similar oscil- encloses the region of the moving magnetic feature, indicated by three lations with 50% reduction in amplitude. The unfiltered inten- partially overlapping circular contours. All three maps, O v 629.7 Å, sity variation of pixel 20 along with the error bars is plotted in He ii 304 Å, and He i 522.2 Å, show a bright patch touching the south the top panel. The large intensity enhancement seen in the unfil- end of the MMF.
tered signal between 30 and 55 min is a manifestation of the O v C.-H. Lin et al.: Transition region counterpart of a moving magnetic feature Fig. 6. The O v 629.7 Å time series of the intensity variation (top), the
de-trended intensity variation (middle), and the relative Doppler veloc-ity with colour bar (bottom). The white rectangular marks the locationof the MMF. The X axis corresponds to the Solar Y coordinates of thepixels along the detector slit, and the Y axis shows the time.
Fig. 5. TRACE 1600 Å channel image taken at 08:30 UT (upper panel)
and 13:40 UT (lower panel).
global wavelet (i.e. the sum of the wavelet power over time ateach oscillation period) is plotted in the lower right panel. Thewavelet spectra are plotted in reversed colours; hence, the darker brightening above the monopole (as seen in the raster image in colours correspond to the higher powers. The white contours en- Fig. 3) crossing the NIS/CDS detector. In other words, the rota- close periods of the oscillations that are above the 95% signif- tion of the Sun brings the monopole to cross the NIS/CDS slit icance level as determined by the randomization method, and during our observation. The dip in the middle of the enhance- the hashed lines mark the region where the edge eﬀect becomes ment may be due to non-uniform brightness in the brightening.
significant (see Torrence & Compo 1998). The relative oscilla- To extract the oscillations that reside on top of the intensity en- tion plots show that the amplitudes inside the bright patch (30– hancement, we removed this dominant feature of the enhance- 65 min) are almost twice as large as those outside (0–30 min).
ment by applying the P700 filter (cf. Sect. 3 for details). We Hence, to obtain the oscillation properties outside the bright also applied the P300 filter in order to examine the oscillations patch, we also examined these weaker oscillations separately in with periods shorter than 300 s. The wavelet analysis results addition to the analysis of the entire signal.
of the two filtered relative oscillations are presented in the two sets of plots following the unfiltered signal in Fig. 7. In each P300-filtered signals reveal that 5-min oscillations (i.e. pe- set, the upper left panel shows the filtered relative oscillations, riods between 250 s and 400 s) are the dominant mode through the wavelet spectrum is illustrated in the bottom panel, and the the entire signal, both inside and outside of the MMF, while C.-H. Lin et al.: Transition region counterpart of a moving magnetic feature Fig. 7. The top row represents the intensity variation of O v 629.7 Å
at Solar Y ≈ 3. The errors are shown as vertical bars. The panels thatfollow are two sets of wavelet analysis of filtered relative intensity os-cillations, P700-filtered (i.e., oscillations with periods longer than 700 sare filtered out) and P300-filtered, as marked.
a multitude of shorter-period oscillations only exist inside theMMF. Figure 7 demonstrates such an example: the P700-filteredwavelet spectrum shows that there are only two major periodbands, 200–300 s and 400–500 s, for the oscillations before30 min while the spectrum of the oscillations between 30 and Fig. 8. The Doppler velocities of the NIS/CDS O v 629.7 Å time se-
60 min extends from 100 s to 700 s. When the modes of periods ries at selected pixels along the slit. The pixels are selected to cover longer than 300 s are filtered out, the strongest oscillation in the the region over the magnetic monopole. The Solar Y coordinate of each P300-filtered signal often shows a periodicity ≈3 min, and the pixel is indicated above the corresponding plot. The blue shifts are rep-resented by negative velocities. The plots show that there are blue shifts oscillation is most significant for the time interval 30–65 min of between 7 and 0 during the time when the slit is over the magnetic the observing sequence, which corresponds to the transit time monopole. (≈35 min to ≈60 min as inferred from the unfiltered oscilla- interval for the MMF across our CDS pixel. This result echoes tions in Fig. 7).
the conclusion by Lin et al. (2005) that 3-min oscillations canexist outside of a sunspot in regions with strong magnetic fields.
Although the signals of He i 522.2 Å are very weak, the He i 522.2 Å reflect the collective conditions from both chromo- wavelet analysis results of He i are consistent with the results of sphere and higher-temperature layers (O'Shea et al. 2002).
O v 629.7 Å, that is, that a dominant 5-min oscillation is seen in the entire signal, but that a more complex spectrum is seen only 4.2.2. Relative material motion inside the moving magnetic monopole. We should point out herethat, in addition to a chromospheric contribution, He i 522.2 Å In Fig. 8, we plot the relative Doppler velocities of O v 629.7 Å can result from particles and radiation from the transition region vs. time at several pixels along the slit. The Solar Y coordi- and corona (Andretta & Jones 1997). Hence, the features seen in nates of the pixels are indicated above the corresponding plots.
C.-H. Lin et al.: Transition region counterpart of a moving magnetic feature The dotted horizontal line marks 0 km s−1, and the negative ve- magnetic canopy. The MMF discussed here appears to be type III locities correspond to blue shifts. The bright patch over the mag- and may have resulted from a Ω-loop emergence, expanding into netic monopole is between 35 min and 60 min. We see that this the upper atmosphere as a result of shocks. Penn & Kuhn (1995) 35–60 min region is relatively blue-shifted between 7 and 0 have seen the bipolar nature of the photospheric magnetic field, and becomes red-shifted below 0, which is also illustrated in whereas the chromospheric field appeared to be unipolar. They Fig. 6. Intriguingly, while the intensity enhancement is localized have also pointed out that their observed MMFs are linked with in the region of MMF detection, large blue shifts are noticeable low lying loops which do not reach to the upper chromosphere before and after the transition of the MMF, that is, between 7 where the He i is formed. These loops must be less than 1500 km and 10 during the first 20 min and between 3 and −7 after high, which is the height where significant He i line formation 60 min of the sequence (see also Fig. 6). The relative Doppler begins, which explain why they could not identify the MMFs in velocities of He i 522.2 Å show the same pattern. Because the the He i line. In recent work, Hagenaar & Frank (2006) identi- velocity is computed relative to the average velocity of the entire fied MMFs in TRACE 1600 Å and studied their presence in high FOV, such blue shifts are not necessarily associated with an up- resolution filtergrams of Ca II K, G-band, Hα, together with ward motion. Nevertheless, the shifts do indicate the existence of vector magnetograms. Their preliminary results suggest strong material flow. The long stripe of the blue shifts extending before correlation between Ca ii K and TRACE 1600 Å with unsigned and after the transition of the MMF may indicate an additional magnetic flux density. Clearly, more simultaneous observations east-west structure guiding/confining the material motion.
of the photosphere and upper atmosphere of MMFs is requiredfrom further SoHO and/or Solar-B observations.
5. Discussions and conclusion
The wavelet analysis on the time series of O v and He i above the monopole reveals that there are significant oscillations During our observation on Feb. 13th, 2004, we detected a in both lines in this region. The two lines show a similar os- positive magnetic monopole (MMF) moving away from the cillation pattern, indicating that the oscillations of the two lines sunspot. The path of the MMF followed the boundary of a super- are related or result from the same source. Although the tem- granulation cell. The supergranular cell broke apart when the perature layer that He i represents is uncertain due to the com- MMF was gone. The MMF also overlapped with a bright patch plex formation mechanisms of the line, the detection confirms seen in both the chromosphere and transition region. The cor- that the oscillations caused by MMF can be seen in the higher relation between the MMF and the atmospheric brightening is further confirmed by the sudden and localized intensity enhance- The wavelet spectra in Fig. 7 show that a dominant 5-min ment seen in the O v intensity time-series during the transition of oscillation runs through the whole time series, both inside and the monopole (cf. Fig. 6). The slight oﬀset between this MMF outside of the monopole region. However, the signal inside the and the bright patch seen in Fig. 3 is likely due to the error in monopole is composed of a wider range of oscillation modes our coordinate determination. However, it is also possible that than the signal outside, which is manifested by the multitude of the magnetic tubes become curved as they reach to the higher strong wavelet peaks within the monopole region (from ≈35 min atmosphere and therefore the higher-temperature apex may ap- to ≈60 min) and the relatively clean spectrum everywhere else.
pear spatially displaced relative to the lower-temperature foot- The dominant 5-min oscillations may be due to the global points, where the MMF is detected in the magnetograms. Such p-mode oscillations. Theoretical models to-date generally depict coincidence in space and time indicates a possible link between MMFs as magnetic knots or kinks resulting from sunspot mag- this moving monopole, the super-granulation boundary, and the netic tubes being strongly disturbed by the mass flows and buoy- strong emission in the chromosphere and transition region lay- ancy. These perturbations can excite a broad spectrum of modes, ers. While several papers (e.g. Harvey & Harvey 1973; Meyer which can travel along the field lines to the higher atmosphere.
et al. 1974; Hagenaar & Shine 2005) have discussed the eﬀect of There has not been any study regarding the temperature of the the super-granular flow on the formation and the travelling paths MMF magnetic structure. Our detection of transition-region os- of MMFs, rather little has been done on the association between cillations spatially and temporally correlated with the existence MMFs and the emissions above the photosphere.
of the MMF implies that MMF field lines may be at the temper- Harvey & Harvey (1973) noted very weak to absent Hα ature of the transition region or that the eﬀects of the fields can emission from MMFs, while Penn & Kuhn (1995) failed to reach up to the transition region.
detect MMFs in He I 10830. Hagenaar & Shine (2003) usingTRACE 171 data showed that coronal emission does not show From the relative Doppler velocities of the time series, we an immediate response to the birth and disappearance of individ- see that a east-west directed stripe over the location of the MMF ual MMF and, therefore, that the role of MMF in the dynamics of is blue-shifted while the regions north of and immediately south upper layers of the atmosphere is unclear. Ryutova & Hagenaar of the MMF are relatively red shifted (cf. Fig. 6). Because the (2005) suggested that there are four types of MMFs: type I are relative Doppler velocity only reflects the relative, not exact, compact pairs of opposite polarity elements that emerge any- motion of the material, the blue shifts could result from ei- where in penumbra or moat region, moving radially outward ther a greater upward motion or a smaller downward motion.
with a velocity exceeding the velocity of ambient flows; type II Nevertheless, Fig. 6 indicates that there are multiple regions with are unipolar features of the same polarity as the sunspot, mov- diﬀerent material motions. Unlike the intensity enhancement, ing outward from the sunspot with higher velocities than type I; the relative blue shifts extend beyond the transition of the MMF, type III are unipolar features but have the polarity opposite to which could indicate an additional east-west directed structure the sunspot's and travel with higher velocities than the other eﬀecting the material motion.
two types of MMFs; type IV appear as compact bipoles flow- The aforementioned phenomena suggest that the MMFs, de- ing into sunspots with an inner foot of a polarity opposite to the spite being small in size, could influence the dynamics in the sunspot's. These diﬀerent types may have quite diﬀerent forma- atmosphere and may contribute to the heating of the upper lay- tion processes, e.g., the lack of a chromospheric component in ers, at least up to the transition region. Hence, it is necessary to some MMF's may be due to a U-loop submergence in part of the conduct an extensive statistical search for the upper-atmospheric C.-H. Lin et al.: Transition region counterpart of a moving magnetic feature counterparts of MMF. Such a study could provide insights into Hagenaar, H. J., & Shine, R. A. 2003, AGU Fall Meeting Abstracts, the link between small photospheric magnetic dynamics and Hagenaar, H. J., & Shine, R. A. 2005, ApJ, 635, 659Harvey, K., & Harvey, J. 1973, Sol. Phys., 28, 61Lee, J. W. 1992, Sol. Phys., 139, 267 Acknowledgements. We would like to thank the CDS team for their help in Lin, C.-H., Banerjee, D., Doyle, J. G., & O'Shea, E. 2005, A&A, 444, 585 obtaining and reducing the data and in particular B. Thompson for advice on Linnell Nemec, A. F., & Nemec, J. M. 1985, AJ, 90, 2317 the line blending issues. CDS, EIT, and MDI are part of SOHO, the Solar Meyer, F., Schmidt, H. U., Wilson, P. R., & Weiss, N. O. 1974, MNRAS, 169, and Heliospheric Observatory, which is a project of international cooperation between ESA and NASA. This work was supported in part by a PRTLI re- O'Shea, E., Banerjee, D., Doyle, J. G., Fleck, B., & Murtagh, F. 2001, A&A, search grant for Grid-enabled Computational Physics of Natural Phenomena (Cosmogrid). CHL was also supported by the grant NSC 94-2119-M-007-001 O'Shea, E., Muglach, K., & Fleck, B. 2002, A&A, 387, 642 from the National Science Council in Taiwan. EOS is supported by PPARC Penn, M. J., & Kuhn, J. R. 1995, ApJ, 441, L51 grant number PP/D001129/1. We wish to thank the Royal Society and the Ravindra, B., Venkatakrishnan, P., & Kumar, B. 2004, Sol. Phys., 225, 47 British Council for funding visits between Armagh Observatory and the Indian Ryutova, M. P. & Hagenaar, H. J. 2005, AGU Spring Meeting Abstracts, Institute of Astrophysics. Research at Armagh Observatory is grant-aided by the N. Ireland Dept. of Culture, Arts and Leisure.
Sheeley, N. R. 1969, Sol. Phys., 9, 347Torrence, C., & Compo, G. P. 1998, Bull. Am. Meteorolog. Soc., 79, 61Yurchyshyn, V. B., Wang, H., & Goode, P. R. 2001, ApJ, 550, 470 Zhang, H., Ai, G., Wang, H., Zirin, H., & Patterson, A. 1992, Sol. Phys., 140, Andretta, V., & Jones, H. P. 1997, ApJ, 489, 375 Zhang, J., Solanki, S. K., & Wang, J. 2003, A&A, 399, 755 Hagenaar, H. J., & Frank, Z. A. 2006, ESA SP-617: SOHO-17, in press
Copyright © 2011 by Rowohlt Verlag GmbH, Reinbek bei Hamburg Eine Weile nachdem er das Wort Pause ausgesprochen hatte, drehte ich durch und landete im Krankenhaus. Er sagte nicht: Ich will dich nie wiedersehen, oder: Es ist aus, doch nach dreißig Jahren Ehe reichte Pause, um aus mir eine Geisteskranke zu machen, in deren Hirn die Gedanken platzten, wild herumfuhrwerkten und von‑einander abprallten wie Popcorn in einer Mikrowellen‑tüte. Diese traurige Feststellung machte ich in meinem Bett in der Psychiatrie, so mit Haldol zugedröhnt, dass ich mich kaum bewegen wollte. Die garstigen rhyth‑mischen Stimmen waren leiser geworden, aber nicht verschwunden, und wenn ich die Augen schloss, sah ich Comicfiguren über rosa Hügel sausen und in blaue Wäl‑der verschwinden. Dr. P. diagnostizierte dann eine akute vorübergehende psychotische Störung, auch bekannt als Durchgangssyndrom, was bedeutet, dass man wirklich verrückt ist, aber nicht lange. Wenn es länger als einen Monat anhält, braucht man ein anderes Etikett. Offenbar gibt es für diese spezielle Form von Störung häufig einen Auslöser oder «Stressor», wie es im psychiatrischen Jargon heißt. In meinem Fall war das Boris, oder vielmehr die Tatsache, dass eben kein Boris da war, dass Boris seine Pause machte. Sie behielten mich anderthalb Wochen da, dann ließen sie mich gehen. Eine Zeitlang wurde ich ambulant behandelt, bis ich Frau Dr. S. mit ihrer tiefen musikalischen Stimme, ihrem verhaltenen Lächeln und ihrem guten Ohr für Lyrik fand. Sie stützte mich, stützt mich eigentlich immer noch.
Studien allgemein – Bedeutung in der Prävention von Krebs Cancer Causes Control. 2015 Nov;26(11):1521-50. doi: 10.1007/s10552-015-0659-4. Epub 2015 Sep 9. A systematic review of dietary, nutritional, and physical activity interventions for the prevention of prostate cancer progression and mortality. Hackshaw-McGeagh LE1,2, Perry RE3, Leach VA4,5, Qandil S4, Jeffreys M4, Martin RM3,4, Lane JA3,4.