# INVERSIONS FOR AVERAGE SUPERGRANULAR FLOWS USING FINITE-FREQUENCY KERNELS

## Abstract

I analyze the maps recording the travel-time shifts caused by averaged plasma anomalies under an 'average supergranule', constructed by means of statistical averaging over 5582 individual supergranules with large divergence signals detected in two months of Helioseismic and Magnetic Imager Dopplergrams. By utilizing a three-dimensional validated time-distance inversion code, I measure a peak vertical velocity of 117 {+-} 2 m s{sup -1} at depths around 1.2 Mm in the center of the supergranule and a root-mean-square vertical velocity of 21 m s{sup -1} over the area of the supergranule. A discrepancy between this measurement and the measured surface vertical velocity (a few m s{sup -1}) can be explained by the existence of the large-amplitude vertical flow under the surface of supergranules with large divergence signals, recently suggested by Duvall and Hanasoge.

- Authors:

- Astronomical Institute, Academy of Sciences of the Czech Republic (v.v.i.), Fricova 298, CZ-25165 Ondrejov (Czech Republic)

- Publication Date:

- OSTI Identifier:
- 22078447

- Resource Type:
- Journal Article

- Journal Name:
- Astrophysical Journal Letters

- Additional Journal Information:
- Journal Volume: 759; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; DEPTH; DISTANCE; GRANULAR MATERIALS; KERNELS; MAPS; PLASMA; SIGNALS; SURFACES; THREE-DIMENSIONAL CALCULATIONS; VELOCITY

### Citation Formats

```
Svanda, Michal, E-mail: michal@astronomie.cz.
```*INVERSIONS FOR AVERAGE SUPERGRANULAR FLOWS USING FINITE-FREQUENCY KERNELS*. United States: N. p., 2012.
Web. doi:10.1088/2041-8205/759/2/L29.

```
Svanda, Michal, E-mail: michal@astronomie.cz.
```*INVERSIONS FOR AVERAGE SUPERGRANULAR FLOWS USING FINITE-FREQUENCY KERNELS*. United States. doi:10.1088/2041-8205/759/2/L29.

```
Svanda, Michal, E-mail: michal@astronomie.cz. Sat .
"INVERSIONS FOR AVERAGE SUPERGRANULAR FLOWS USING FINITE-FREQUENCY KERNELS". United States. doi:10.1088/2041-8205/759/2/L29.
```

```
@article{osti_22078447,
```

title = {INVERSIONS FOR AVERAGE SUPERGRANULAR FLOWS USING FINITE-FREQUENCY KERNELS},

author = {Svanda, Michal, E-mail: michal@astronomie.cz},

abstractNote = {I analyze the maps recording the travel-time shifts caused by averaged plasma anomalies under an 'average supergranule', constructed by means of statistical averaging over 5582 individual supergranules with large divergence signals detected in two months of Helioseismic and Magnetic Imager Dopplergrams. By utilizing a three-dimensional validated time-distance inversion code, I measure a peak vertical velocity of 117 {+-} 2 m s{sup -1} at depths around 1.2 Mm in the center of the supergranule and a root-mean-square vertical velocity of 21 m s{sup -1} over the area of the supergranule. A discrepancy between this measurement and the measured surface vertical velocity (a few m s{sup -1}) can be explained by the existence of the large-amplitude vertical flow under the surface of supergranules with large divergence signals, recently suggested by Duvall and Hanasoge.},

doi = {10.1088/2041-8205/759/2/L29},

journal = {Astrophysical Journal Letters},

issn = {2041-8205},

number = 2,

volume = 759,

place = {United States},

year = {2012},

month = {11}

}