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Your search keyword '"Thiemann, E."' showing total 18 results
Start Over Author "Thiemann, E." Journal geophysical research letters
18 results on '"Thiemann, E."'

1. Retrieval of CO Relative Column Abundance in the Martian Thermosphere From FUV Disk Observations by EMM EMUS

Author

Evans, J. S., primary, Correira, J., additional, Deighan, J., additional, Jain, S., additional, Al Matroushi, H., additional, Al Mazmi, H., additional, Chaffin, M., additional, Curry, S., additional, England, S., additional, Eparvier, F., additional, Fillingim, M., additional, Forget, F., additional, Holsclaw, G., additional, Lillis, R., additional, Lootah, F., additional, and Thiemann, E., additional

Published
2022
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2. An Artificial Neural Network for Inferring Solar Wind Proxies at Mars

Author

Ruhunusiri, Suranga, Halekas, Jasper S, Espley, Jared R, Eparvier, Francis G, Brain, D, Mazelle, C, Harada, Y, DiBraccio, G. A, Dong, Y, Ma, Y, Thiemann, E. M. B, Mitchell, D. L, and Jakosky, B. M

Subjects
Lunar And Planetary Science And Exploration
Abstract

We present a novel method to determine solar wind proxies from sheath measurements at Mars. Specifically, we develop an artificial neural network (ANN) to simultaneously infer seven solar wind proxies: ion density, ion speed, ion temperature, and interplanetary magnetic field magnitude and its vector components, using spacecraft measurements of ion moments, magnetic field magnitude, magnetic field components in the sheath, and the solar extreme ultraviolet flux. The ANN was trained and tested using3 years of data from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. When compared with MAVEN spacecraft's in situ measured values of the solar wind parameters, we find that the ANN proxies for the solar wind ion density, ion speed, ion temperature, and interplanetary magnetic field magnitude havepercentage differences of 50% or less for 84.4%, 99.9%, 86.8%, and 79.8% of the instances, respectively. Forthe cone angle and clock angle proxies, 69.1% and 53.3% of instances, respectively, have angle differences of 30* or less.

Published
2018
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6. The Mars Topside Ionosphere Response to the X8.2 Solar Flare of 10 September 2017

Author

Thiemann, E. M. B., primary, Andersson, L., additional, Lillis, R., additional, Withers, P., additional, Xu, S., additional, Elrod, M., additional, Jain, S., additional, Pilinski, M. D., additional, Pawlowski, D., additional, Chamberlin, P. C., additional, Eparvier, F. G., additional, Benna, M., additional, Fowler, C., additional, Curry, S., additional, Peterson, W. K., additional, and Deighan, J., additional

Published
2018
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7. Martian Thermospheric Response to an X8.2 Solar Flare on 10 September 2017 as Seen by MAVEN/IUVS

Author

Jain, S. K., primary, Deighan, J., additional, Schneider, N. M., additional, Stewart, A. I. F., additional, Evans, J. S., additional, Thiemann, E. M. B., additional, Chaffin, M. S., additional, Crismani, M., additional, Stevens, M. H., additional, Elrod, M. K., additional, Stiepen, A., additional, McClintock, W. E., additional, Lo, D. Y., additional, Clarke, J. T., additional, Eparvier, F. G., additional, Lefévre, F., additional, Montmessin, F., additional, Holsclaw, G. M., additional, Chamberlin, P. C., additional, and Jakosky, B. M., additional

Published
2018
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8. Neutral density response to solar flares at Mars

Author

Thiemann, E. M. B., primary, Eparvier, F. G., additional, Andersson, L. A., additional, Fowler, C. M., additional, Peterson, W. K., additional, Mahaffy, P. R., additional, England, S. L., additional, Larson, D. E., additional, Lo, D. Y., additional, Schneider, N. M., additional, Deighan, J. I., additional, McClintock, W. E., additional, and Jakosky, B. M., additional

Published
2015
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9. The structure and variability of Mars upper atmosphere as seen in MAVEN/IUVS dayglow observations

Author

Jain, S. K., primary, Stewart, A. I. F., additional, Schneider, N. M., additional, Deighan, J., additional, Stiepen, A., additional, Evans, J. S., additional, Stevens, M. H., additional, Chaffin, M. S., additional, Crismani, M., additional, McClintock, W. E., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Lo, D. Y., additional, Lefèvre, F., additional, Montmessin, F., additional, Thiemann, E. M. B., additional, Eparvier, F., additional, and Jakosky, B. M., additional

Published
2015
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10. Retrieval of CO2 and N2 in the Martian thermosphere using dayglow observations by IUVS on MAVEN

Author

Evans, J. S., primary, Stevens, M. H., additional, Lumpe, J. D., additional, Schneider, N. M., additional, Stewart, A. I. F., additional, Deighan, J., additional, Jain, S. K., additional, Chaffin, M. S., additional, Crismani, M., additional, Stiepen, A., additional, McClintock, W. E., additional, Holsclaw, G. M., additional, Lefèvre, F., additional, Lo, D. Y., additional, Clarke, J. T., additional, Eparvier, F. G., additional, Thiemann, E. M. B., additional, Chamberlin, P. C., additional, Bougher, S. W., additional, Bell, J. M., additional, and Jakosky, B. M., additional

Published
2015
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11. Three‐dimensional structure in the Mars H corona revealed by IUVS on MAVEN

Author

Chaffin, M. S., primary, Chaufray, J. Y., additional, Deighan, J., additional, Schneider, N. M., additional, McClintock, W. E., additional, Stewart, A. I. F., additional, Thiemann, E., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Jain, S. K., additional, Crismani, M. M. J., additional, Stiepen, A., additional, Montmessin, F., additional, Eparvier, F. G., additional, Chamberlain, P. C., additional, and Jakosky, B. M., additional

Published
2015
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12. Study of the Martian cold oxygen corona from the O I 130.4 nm by IUVS/MAVEN

Author

Chaufray, J. Y., primary, Deighan, J., additional, Chaffin, M. S., additional, Schneider, N. M., additional, McClintock, W. E., additional, Stewart, A. I. F., additional, Jain, S. K., additional, Crismani, M., additional, Stiepen, A., additional, Holsclaw, G. M., additional, Clarke, J. T., additional, Montmessin, F., additional, Eparvier, F. G., additional, Thiemann, E. M. B., additional, Chamberlin, P. C., additional, and Jakosky, B. M., additional

Published
2015
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13. MAVEN insights into oxygen pickup ions at Mars

Author

Rahmati, A., primary, Larson, D. E., additional, Cravens, T. E., additional, Lillis, R. J., additional, Dunn, P. A., additional, Halekas, J. S., additional, Connerney, J. E., additional, Eparvier, F. G., additional, Thiemann, E. M. B., additional, and Jakosky, B. M., additional

Published
2015
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14. MAVEN IUVS observation of the hot oxygen corona at Mars

Author

Deighan, J., primary, Chaffin, M. S., additional, Chaufray, J.‐Y., additional, Stewart, A. I. F., additional, Schneider, N. M., additional, Jain, S. K., additional, Stiepen, A., additional, Crismani, M., additional, McClintock, W. E., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Montmessin, F., additional, Eparvier, F. G., additional, Thiemann, E. M. B., additional, Chamberlin, P. C., additional, and Jakosky, B. M., additional

Published
2015
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17. Retrieval of CO2and N2in the Martian thermosphere using dayglow observations by IUVS on MAVEN

Author

Evans, J. S., Stevens, M. H., Lumpe, J. D., Schneider, N. M., Stewart, A. I. F., Deighan, J., Jain, S. K., Chaffin, M. S., Crismani, M., Stiepen, A., McClintock, W. E., Holsclaw, G. M., Lefèvre, F., Lo, D. Y., Clarke, J. T., Eparvier, F. G., Thiemann, E. M. B., Chamberlin, P. C., Bougher, S. W., Bell, J. M., and Jakosky, B. M.

Abstract

We present direct number density retrievals of carbon dioxide (CO2) and molecular nitrogen (N2) for the upper atmosphere of Mars using limb scan observations during October and November 2014 by the Imaging Ultraviolet Spectrograph on board NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We use retrieved CO2densities to derive temperature variability between 170 and 220 km. Analysis of the data shows (1) low‐mid latitude northern hemisphere CO2densities at 170 km vary by a factor of about 2.5, (2) on average, the N2/CO2increases from 0.042 ± 0.017 at 130 km to 0.12 ± 0.06 at 200 km, and (3) the mean upper atmospheric temperature is 324 ± 22 K for local times near 14:00. Retrieved CO2densities at 170 km vary by a factor of about 2.5On average, N2/CO2increases from 4% at 130 km to 12% at 200 kmMean Martian upper atmospheric temperature over the sampled time frame is 324 {±} 22 K

Published
2015
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18. Mars Upper Atmospheric Responses to the 10 September 2017 Solar Flare: A Global, Time-Dependent Simulation.

Author

Fang X, Pawlowski D, Ma Y, Bougher S, Thiemann E, Eparvier F, Wang W, Dong C, Lee CO, Dong Y, Benna M, Elrod M, Chamberlin P, Mahaffy P, and Jakosky B

Abstract

We report the first global, time-dependent simulation of the Mars upper atmospheric responses to a realistic solar flare event, an X8.2 eruption on 10 September 2017. The Mars Global Ionosphere-Thermosphere Model runs with realistically specified flare irradiance, giving results in reasonably good agreement with the Mars Atmosphere and Volatile EvolutioN spacecraft measurements. It is found that the ionized and neutral regimes of the upper atmosphere are significantly disturbed by the flare but react differently. The ionospheric electron density enhancement is concentrated below ~110-km altitude due to enhanced solar X-rays, closely following the time evolution of the flare. The neutral atmospheric perturbation increases with altitude and is important above ~150-km altitude, in association with atmospheric upwelling driven by solar extreme ultraviolet heating. It takes ~2.5 hr past the flare peak to reach the maximum disturbance and then additional ~10 hr to generally settle down to preflare levels.

Published
2019
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