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Your search keyword '"Kepko, E. L."' showing total 6 results
Start Over Author "Kepko, E. L." Publisher johns hopkins univ, appl phys lab, laurel, md usa.
6 results on '"Kepko, E. L."'

1. Transient, small-scale field-aligned currents in the plasma sheet boundary layer during storm time substorms

Author

Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., Saito, Y., Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., and Saito, Y.

Abstract

We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward plasma sheet expansion. They coincide with upward field-aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.

Published
2016
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2. Multispacecraft analysis of dipolarization fronts and associated whistler wave emissions using MMS data

Author

Breuillard, H., Le Contel, O., Retino, A., Chasapis, A., Chust, T., Mirioni, L., Graham, Daniel B., Wilder, F. D., Cohen, I., Vaivads, Andris, Khotyaintsev, Yuri V., Lindqvist, P. -A, Marklund, G. T., Burch, J. L., Torbert, R. B., Ergun, R. E., Goodrich, K. A., Macri, J., Needell, J., Chutter, M., Rau, D., Dors, I., Russell, C. T., Magnes, W., Strangeway, R. J., Bromund, K. R., Plaschke, F., Fischer, D., Leinweber, H. K., Anderson, B. J., Le, G., Slavin, J. A., Kepko, E. L., Baumjohann, W., Mauk, B., Fuselier, S. A., Nakamura, R., Breuillard, H., Le Contel, O., Retino, A., Chasapis, A., Chust, T., Mirioni, L., Graham, Daniel B., Wilder, F. D., Cohen, I., Vaivads, Andris, Khotyaintsev, Yuri V., Lindqvist, P. -A, Marklund, G. T., Burch, J. L., Torbert, R. B., Ergun, R. E., Goodrich, K. A., Macri, J., Needell, J., Chutter, M., Rau, D., Dors, I., Russell, C. T., Magnes, W., Strangeway, R. J., Bromund, K. R., Plaschke, F., Fischer, D., Leinweber, H. K., Anderson, B. J., Le, G., Slavin, J. A., Kepko, E. L., Baumjohann, W., Mauk, B., Fuselier, S. A., and Nakamura, R.

Abstract

Dipolarization fronts (DFs), embedded in bursty bulk flows, play a crucial role in Earth's plasma sheet dynamics because the energy input from the solar wind is partly dissipated in their vicinity. This dissipation is in the form of strong low-frequency waves that can heat and accelerate energetic electrons up to the high-latitude plasma sheet. However, the dynamics of DF propagation and associated low-frequency waves in the magnetotail are still under debate due to instrumental limitations and spacecraft separation distances. In May 2015 the Magnetospheric Multiscale (MMS) mission was in a string-of-pearls configuration with an average intersatellite distance of 160km, which allows us to study in detail the microphysics of DFs. Thus, in this letter we employ MMS data to investigate the properties of dipolarization fronts propagating earthward and associated whistler mode wave emissions. We show that the spatial dynamics of DFs are below the ion gyroradius scale in this region (approximate to 500km), which can modify the dynamics of ions in the vicinity of the DF (e.g., making their motion nonadiabatic). We also show that whistler wave dynamics have a temporal scale of the order of the ion gyroperiod (a few seconds), indicating that the perpendicular temperature anisotropy can vary on such time scales.

Published
2016
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3. Transient, small-scale field-aligned currents in the plasma sheet boundary layer during storm time substorms

Author

Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., Saito, Y., Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., and Saito, Y.

Abstract

We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward plasma sheet expansion. They coincide with upward field-aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.

Published
2016
Full Text
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4. Transient, small-scale field-aligned currents in the plasma sheet boundary layer during storm time substorms

Author

Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., Saito, Y., Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., and Saito, Y.

Abstract

We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward plasma sheet expansion. They coincide with upward field-aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.

Published
2016
Full Text
View/download PDF

5. Transient, small-scale field-aligned currents in the plasma sheet boundary layer during storm time substorms

Author

Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., Saito, Y., Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., and Saito, Y.

Abstract

We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward plasma sheet expansion. They coincide with upward field-aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.

Published
2016
Full Text
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6. Transient, small-scale field-aligned currents in the plasma sheet boundary layer during storm time substorms

Author

Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., Saito, Y., Nakamura, R., Sergeev, V. A., Baumjohann, W., Plaschke, F., Magnes, W., Fischer, D., Varsani, A., Schmid, D., Nakamura, T. K. M., Russell, C. T., Strangeway, R. J., Leinweber, H. K., Le, G., Bromund, K. R., Pollock, C. J., Giles, B. L., Dorelli, J. C., Gershman, D. J., Paterson, W., Avanov, L. A., Fuselier, S. A., Genestreti, K., Burch, J. L., Torbert, R. B., Chutter, M., Argall, M. R., Anderson, B. J., Lindqvist, P. -A, Marklund, G. T., Khotyaintsev, Yuri, Mauk, B. H., Cohen, I. J., Baker, D. N., Jaynes, A. N., Ergun, R. E., Singer, H. J., Slavin, J. A., Kepko, E. L., Moore, T. E., Lavraud, B., Coffey, V., and Saito, Y.

Abstract

We report on field-aligned current observations by the four Magnetospheric Multiscale (MMS) spacecraft near the plasma sheet boundary layer (PSBL) during two major substorms on 23 June 2015. Small-scale field-aligned currents were found embedded in fluctuating PSBL flux tubes near the separatrix region. We resolve, for the first time, short-lived earthward (downward) intense field-aligned current sheets with thicknesses of a few tens of kilometers, which are well below the ion scale, on flux tubes moving equatorward/earthward during outward plasma sheet expansion. They coincide with upward field-aligned electron beams with energies of a few hundred eV. These electrons are most likely due to acceleration associated with a reconnection jet or high-energy ion beam-produced disturbances. The observations highlight coupling of multiscale processes in PSBL as a consequence of magnetotail reconnection.

Published
2016
Full Text
View/download PDF

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