IRIS-6: The Chromosphere

20 Jun 2016, 09:00 → 23 Jun 2016, 17:00 Europe/Stockholm

FR4 (AlbaNova University Centre)

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Contact: iris-6.workshop@astro.su.se

Monday, 20 June

09:53 → 09:53 Chromospheric response to prolonged small-scale reconnections

Magnetic reconnection is thought to be responsible for eruptive events on the Sun, from large-scale CMEs to small-scale events that are barely resolved. The height in the solar atmosphere where the reconnection takes place may significantly influence the morphology and appearance of the events. This might be the main distinction between events such as e.g. Ellerman bombs, IRIS bombs, or explosive events which are observed in spectral lines forming at different temperatures showing different line profile characteristics. Here we report a prolonged reconnection event caused by a magnetic feature moving from a sunspot to an adjacent pore. Data-driven nonlinear force-free field extrapolations and magneto-frictional models suggest that the strong dominant sunspot and the pore of the same polarity lead to a canopy-type field structure at low heights. The moving magnetic feature of the opposite polarity reconnects with the overlying canopy. The models suggest a height of the reconnection only about 500 km above tau=1. The IRIS observations of this event show complex Mg II, C II, and Si IV line profiles, in part similar to those reported earlier for IRIS bombs. We find evidence for strong spatial, velocity discontinuities from red to blueshifts in the Si IV Dopplergrams at the reconnection site. Additionally, multiple blueshifted components along the same line of sight are also observed. Further, there is evidence that the downflowing plasma from the reconnection site interacts with chromospheric plasma, increasing the apparent brightness of the structure. The magnetic modelling of these events supports the earlier suggestions that the location of the reconnection of these active region UV bursts is very low in the atmosphere, in the low chromosphere or even in the photosphere. Small-scale events like this may give insights into the dynamics and complex evolution of large-scale eruptive events on the Sun.

10:53 → 10:53 Chromospheric response to prolonged small-scale reconnections

Magnetic reconnection is thought to be responsible for eruptive events on the Sun, from large-scale CMEs to small-scale events that are barely resolved. The height in the solar atmosphere where the reconnection takes place may significantly influence the morphology and appearance of the events. This might be the main distinction between events such as e.g. Ellerman bombs, IRIS bombs, or explosive events which are observed in spectral lines forming at different temperatures showing different line profile characteristics. Here we report a prolonged reconnection event caused by a magnetic feature moving from a sunspot to an adjacent pore. Data-driven nonlinear force-free field extrapolations and magneto-frictional models suggest that the strong dominant sunspot and the pore of the same polarity lead to a canopy-type field structure at low heights. The moving magnetic feature of the opposite polarity reconnects with the overlying canopy. The models suggest a height of the reconnection only about 500 km above tau=1. The IRIS observations of this event show complex Mg II, C II, and Si IV line profiles, in part similar to those reported earlier for IRIS bombs. We find evidence for strong spatial, velocity discontinuities from red to blueshifts in the Si IV Dopplergrams at the reconnection site. Additionally, multiple blueshifted components along the same line of sight are also observed. Further, there is evidence that the downflowing plasma from the reconnection site interacts with chromospheric plasma, increasing the apparent brightness of the structure. The magnetic modelling of these events supports the earlier suggestions that the location of the reconnection of these active region UV bursts is very low in the atmosphere, in the low chromosphere or even in the photosphere. Small-scale events like this may give insights into the dynamics and complex evolution of large-scale eruptive events on the Sun.

Monday, 20 June

09:00 → 12:30 test session

11:00 → 11:00 Chromospheric response to prolonged small-scale reconnections

Magnetic reconnection is thought to be responsible for eruptive events on the Sun, from large-scale CMEs to small-scale events that are barely resolved. The height in the solar atmosphere where the reconnection takes place may significantly influence the morphology and appearance of the events. This might be the main distinction between events such as e.g. Ellerman bombs, IRIS bombs, or explosive events which are observed in spectral lines forming at different temperatures showing different line profile characteristics. Here we report a prolonged reconnection event caused by a magnetic feature moving from a sunspot to an adjacent pore. Data-driven nonlinear force-free field extrapolations and magneto-frictional models suggest that the strong dominant sunspot and the pore of the same polarity lead to a canopy-type field structure at low heights. The moving magnetic feature of the opposite polarity reconnects with the overlying canopy. The models suggest a height of the reconnection only about 500 km above tau=1. The IRIS observations of this event show complex Mg II, C II, and Si IV line profiles, in part similar to those reported earlier for IRIS bombs. We find evidence for strong spatial, velocity discontinuities from red to blueshifts in the Si IV Dopplergrams at the reconnection site. Additionally, multiple blueshifted components along the same line of sight are also observed. Further, there is evidence that the downflowing plasma from the reconnection site interacts with chromospheric plasma, increasing the apparent brightness of the structure. The magnetic modelling of these events supports the earlier suggestions that the location of the reconnection of these active region UV bursts is very low in the atmosphere, in the low chromosphere or even in the photosphere. Small-scale events like this may give insights into the dynamics and complex evolution of large-scale eruptive events on the Sun.

11:00 → 11:00 Chromospheric response to prolonged small-scale reconnections

Magnetic reconnection is thought to be responsible for eruptive events on the Sun, from large-scale CMEs to small-scale events that are barely resolved. The height in the solar atmosphere where the reconnection takes place may significantly influence the morphology and appearance of the events. This might be the main distinction between events such as e.g. Ellerman bombs, IRIS bombs, or explosive events which are observed in spectral lines forming at different temperatures showing different line profile characteristics. Here we report a prolonged reconnection event caused by a magnetic feature moving from a sunspot to an adjacent pore. Data-driven nonlinear force-free field extrapolations and magneto-frictional models suggest that the strong dominant sunspot and the pore of the same polarity lead to a canopy-type field structure at low heights. The moving magnetic feature of the opposite polarity reconnects with the overlying canopy. The models suggest a height of the reconnection only about 500 km above tau=1. The IRIS observations of this event show complex Mg II, C II, and Si IV line profiles, in part similar to those reported earlier for IRIS bombs. We find evidence for strong spatial, velocity discontinuities from red to blueshifts in the Si IV Dopplergrams at the reconnection site. Additionally, multiple blueshifted components along the same line of sight are also observed. Further, there is evidence that the downflowing plasma from the reconnection site interacts with chromospheric plasma, increasing the apparent brightness of the structure. The magnetic modelling of these events supports the earlier suggestions that the location of the reconnection of these active region UV bursts is very low in the atmosphere, in the low chromosphere or even in the photosphere. Small-scale events like this may give insights into the dynamics and complex evolution of large-scale eruptive events on the Sun.

Tuesday, 21 June

11:00 → 11:00 Chromospheric response to prolonged small-scale reconnections

Magnetic reconnection is thought to be responsible for eruptive events on the Sun, from large-scale CMEs to small-scale events that are barely resolved. The height in the solar atmosphere where the reconnection takes place may significantly influence the morphology and appearance of the events. This might be the main distinction between events such as e.g. Ellerman bombs, IRIS bombs, or explosive events which are observed in spectral lines forming at different temperatures showing different line profile characteristics. Here we report a prolonged reconnection event caused by a magnetic feature moving from a sunspot to an adjacent pore. Data-driven nonlinear force-free field extrapolations and magneto-frictional models suggest that the strong dominant sunspot and the pore of the same polarity lead to a canopy-type field structure at low heights. The moving magnetic feature of the opposite polarity reconnects with the overlying canopy. The models suggest a height of the reconnection only about 500 km above tau=1. The IRIS observations of this event show complex Mg II, C II, and Si IV line profiles, in part similar to those reported earlier for IRIS bombs. We find evidence for strong spatial, velocity discontinuities from red to blueshifts in the Si IV Dopplergrams at the reconnection site. Additionally, multiple blueshifted components along the same line of sight are also observed. Further, there is evidence that the downflowing plasma from the reconnection site interacts with chromospheric plasma, increasing the apparent brightness of the structure. The magnetic modelling of these events supports the earlier suggestions that the location of the reconnection of these active region UV bursts is very low in the atmosphere, in the low chromosphere or even in the photosphere. Small-scale events like this may give insights into the dynamics and complex evolution of large-scale eruptive events on the Sun.

11:00 → 11:00 Chromospheric response to prolonged small-scale reconnections

Magnetic reconnection is thought to be responsible for eruptive events on the Sun, from large-scale CMEs to small-scale events that are barely resolved. The height in the solar atmosphere where the reconnection takes place may significantly influence the morphology and appearance of the events. This might be the main distinction between events such as e.g. Ellerman bombs, IRIS bombs, or explosive events which are observed in spectral lines forming at different temperatures showing different line profile characteristics. Here we report a prolonged reconnection event caused by a magnetic feature moving from a sunspot to an adjacent pore. Data-driven nonlinear force-free field extrapolations and magneto-frictional models suggest that the strong dominant sunspot and the pore of the same polarity lead to a canopy-type field structure at low heights. The moving magnetic feature of the opposite polarity reconnects with the overlying canopy. The models suggest a height of the reconnection only about 500 km above tau=1. The IRIS observations of this event show complex Mg II, C II, and Si IV line profiles, in part similar to those reported earlier for IRIS bombs. We find evidence for strong spatial, velocity discontinuities from red to blueshifts in the Si IV Dopplergrams at the reconnection site. Additionally, multiple blueshifted components along the same line of sight are also observed. Further, there is evidence that the downflowing plasma from the reconnection site interacts with chromospheric plasma, increasing the apparent brightness of the structure. The magnetic modelling of these events supports the earlier suggestions that the location of the reconnection of these active region UV bursts is very low in the atmosphere, in the low chromosphere or even in the photosphere. Small-scale events like this may give insights into the dynamics and complex evolution of large-scale eruptive events on the Sun.