Slender Ca ii H Fibrils Mapping Magnetic Fields in the Low Solar Chromosphere

Jafarzadeh, S.; Rutten, R. J.; Solanki, S. K.; Wiegelmann, T.; Riethmüller, T. L.; Noort, M. van; Szydlarski, Mikołaj; Rodríguez, J. Blanco; Barthol, P.; Iniesta, J. C. del Toro; Gandorfer, A.; Gizon, Laurent; Hirzberger, J.; Knölker, M.; Pillet, V. Martínez; Suárez, D. Orozco; Schmidt, Wolfgang

doi:10.3847/1538-4365/229/1/11

Cited by 43 publications

(48 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our observations cannot, however, clarify whether this energy is dissipated in the sampled atmospheric layers. The apparently almost horizontalorientationof the majority of the SCFs studied here, many of which connect back to the solar surface as low-lying loops (see Jafarzadeh et al 2017a), suggest that the waves propagating along them may not reach the upper atmosphere. Rather, they play a role in heating their local surroundings, if they release their energy at these layers.…”

Section: The Structures Listed Inmentioning

confidence: 88%

“…These events may, however, share some apparent and/or physical characteristics (e.g., both types of underlying fibrils are observed as short-lived, dynamic, thin and bright elongated features in the Ca II H passband). Jafarzadeh et al (2017a)showedthat the SUNRISE/SuFI SCFs map the magnetic fields in the low solar chromosphere.…”

Section: The Structures Listed Inmentioning

confidence: 99%

“…Rather, they play a role in heating their local surroundings, if they release their energy at these layers. Jafarzadeh et al (2017a) showed with the help of the magnetostatic solution of Wiegelmann et al (2017) that the shorter SCFs map fields that are more vertical. A number of the transverse waves we have identified are found along these short fibrils.…”

Section: The Structures Listed Inmentioning

confidence: 99%

See 2 more Smart Citations

Transverse Oscillations in Slender Ca ii H Fibrils Observed with Sunrise/SuFI

Jafarzadeh

Solanki

Gafeira

et al. 2017

ApJS

Self Cite

View full text Add to dashboard Cite

We present observations of transverse oscillations in slender Ca IIH fibrils (SCFs) in the lower solar chromosphere. We use a 1 hr long time series of high-(spatial and temporal-) resolutionseeing-free observations in a 1.1 Å wide passband covering the line core of Ca IIH 3969 Å from the second flight of the SUNRISE balloon-borne solar observatory. The entire field of view, spanning the polarity inversion line of an active region close to the solar disk center, is covered with bright, thin, and very dynamic fine structures. Our analysis reveals the prevalence of transverse waves in SCFs with median amplitudes and periods on the order of 2.4±0.8 km s −1 and 83±29 s, respectively (with standard deviations given as uncertainties). We find that the transverse waves often propagate along (parts of) the SCFs with median phase speeds of 9±14 km s −1. While the propagation is only in one direction along the axis in some of the SCFs, propagating waves in both directions, as well as standing waves are also observed. The transverse oscillations are likely Alfvénic and are thought to be representative of magnetohydrodynamic kink waves. The wave propagation suggests that the rapidhigh-frequency transverse waves,often produced in the lower photosphere, can penetrate into the chromospherewith an estimated energy flux of ≈15 kW m −2. Characteristics of these waves differ from those reported for other fibrillar structures, which, however, were observed mainly in the upper solar chromosphere.

show abstract

Section: The Structures Listed Inmentioning

confidence: 88%

Section: The Structures Listed Inmentioning

confidence: 99%

Section: The Structures Listed Inmentioning

confidence: 99%

See 1 more Smart Citation

Transverse Oscillations in Slender Ca ii H Fibrils Observed with Sunrise/SuFI

Jafarzadeh

Solanki

Gafeira

et al. 2017

ApJS

Self Cite

View full text Add to dashboard Cite

show abstract

“…These structures, seen in radiation, are thought to follow magnetic field lines (e.g., Jafarzadeh et al 2017b) anchored in photospheric magnetic flux concentrations, or in the weaker internetwork elements (Wiegelmann et al 2010). Except for regions with large magnetic flux concentrations, such as sunspots or large pores, these structures play an important role in transporting the energy from the solar surface to the chromosphere and to the corona, either as a channel for the propagation of waves (e.g., van Ballegooijen et al 2011), or as the location for small-scale reconnection events (Gold 1964;Parker 1972).…”

Section: Introductionmentioning

confidence: 99%

Morphological Properties of Slender Ca H Fibrils Observed by Sunrise II

Gafeira¹,

Lagg²,

Solanki³

et al. 2017

ApJS

Self Cite

View full text Add to dashboard Cite

We use seeing-free high spatial resolution Ca II H data obtained by the SUNRISE observatory to determine properties of slender fibrils in the lower solar chromosphere. In this work we use intensity images taken with the SUFI instrument in the Ca II H line during the second scientific flight of the SUNRISE observatory to identify and track elongated bright structures. After identification, we analyze theses structures to extract their morphological properties. We identify 598 slender Ca II H fibrils (SCFs) with an average width of around 180 km, length between 500 and 4000 km, average lifetime of ≈400 s, and average curvature of 0.002 arcsec −1 . The maximum lifetime of the SCFs within our time series of 57 minutes is ≈2000 s. We discuss similarities and differences of the SCFs with other small-scale, chromospheric structures such as spicules of type I and II, or Ca II K fibrils.

show abstract

“…Their range of periods overlaps with those of the MBPs we observe in this study. The slender CaIIH fibrils have been shown to outline the nearly horizontal magnetic field lines in the low solar chromosphere, slightly higher than the heights, where our CaIIH MBPs were sampled (Jafarzadeh et al 2017a). Since such fibrils have footpoints in photospheric magnetic features, such as MBPs, we speculate that waves of the type observed here partly continue into the chromosphere and may become visible as oscillations of fibrils.…”

Section: Comparisons and Discussionmentioning

confidence: 99%

High-frequency Oscillations in Small Magnetic Elements Observed with Sunrise/SuFI

Jafarzadeh¹,

Solanki²,

Stangalini³

et al. 2017

ApJS

Self Cite

View full text Add to dashboard Cite

We characterize waves in small magnetic elements and investigate their propagation in the lower solar atmosphere from observations at high spatial and temporal resolution. We use the wavelet transform to analyze oscillations of both horizontal displacement and intensity in magnetic bright points found in the 300nm and the CaIIH 396.8nm passbands of the filter imager on board the SUNRISE balloon-borne solar observatory. Phase differences between the oscillations at the two atmospheric layers corresponding to the two passbands reveal upward propagating waves at high frequencies (up to 30 mHz). Weak signatures of standing as well as downward propagating waves are also obtained. Both compressible and incompressible (kink) waves are found in the smallscale magnetic features. The two types of waves have different, though overlapping, period distributions. Two independent estimates give a height difference of approximately 450±100km between the two atmospheric layers sampled by the employed spectral bands. This value, together with the determined short travel times of the transverse and longitudinal waves provide us with phase speeds of 29±2km s −1 and 31±2km s −1 , respectively. We speculate that these phase speeds may not reflect the true propagation speeds of the waves. Thus, effects such as the refraction of fast longitudinal waves may contribute to an overestimate of the phase speed.

show abstract

Slender Ca ii H Fibrils Mapping Magnetic Fields in the Low Solar Chromosphere

Cited by 43 publications

References 76 publications

Transverse Oscillations in Slender Ca ii H Fibrils Observed with Sunrise/SuFI

Transverse Oscillations in Slender Ca ii H Fibrils Observed with Sunrise/SuFI

Morphological Properties of Slender Ca H Fibrils Observed by Sunrise II

High-frequency Oscillations in Small Magnetic Elements Observed with Sunrise/SuFI

Contact Info

Product

Resources

About