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1. Observation of a spectral hardening in cosmic ray boron spectrum with the DAMPE space mission

Author

DAMPE Collaboration, Alemanno, F., Altomare, C., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Boutin, H., Cagnoli, I., Cai, M. S., Casilli, E., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Chen, Z. X., Coppin, P., Cui, M. Y., Cui, T. S., Cui, Y. X., De Mitri, I., de Palma, F., Di Giovanni, A., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., Fan, R. R., Fan, Y. Z., Fang, F., Fang, K., Feng, C. Q., Feng, L., Frieden, J. M., Fusco, P., Gao, M., Gargano, F., Ghose, E., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, L. Y., Jiang, Y. Z., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, W. H., Li, W. L., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, Y., Loparco, F., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Putti-Garcia, E., Qiao, R., Rao, J. N., Sarkar, R., Savina, P., Serpolla, A., Shangguan, Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, H. R., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, J. Z., Wang, L. G., Wang, S., Wang, X. L., Wang, Y. F., Wang, Y., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, S. S., Wu, X., Xia, Z. Q., Xu, E. H., Xu, H. T., Xu, J., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, Q., Yue, C., Zang, J. J., Zhang, S. X., Zhang, W. Z., Zhang, Yan, Zhang, Yi, Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

Secondary cosmic ray fluxes are important probes of the propagation and interaction of high-energy particles in the Galaxy. Recent measurements of primary and secondary cosmic ray nuclei have revealed unexpected spectral features that demand a deeper understanding. In this work we report the direct measurement of the cosmic ray boron spectrum from 10 GeV/n to 8 TeV/n with eight years of data collected by the Dark Matter Particle Explorer (DAMPE) mission. The measured spectrum shows an evident hardening at $182\pm24$ GeV/n with a spectral power index of $\gamma_1 = 3.02 \pm 0.01$ before the break and an index change of $\Delta \gamma = 0.31 \pm 0.05$ after the break. A simple power law model is disfavored at a confidence level of 8$\sigma$. Compared with the hardenings measured in the DAMPE proton and helium spectra, the secondary boron spectrum hardens roughly twice as much as these primaries, which is consistent with a propagation related mechanism to interpret the spectral hardenings of cosmic rays observed at hundreds of GeV/n., Comment: 10 pages, 10 figures, submitted to PRL

Published
2024

2. Hadronic cross section measurements with the DAMPE space mission using 20GeV-10TeV cosmic-ray protons and $^4$He

Author

Alemanno, F., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cagnoli, I., Cai, M. S., Casilli, E., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Coppin, P., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., De Benedittis, A., De Mitri, I., de Palma, F., Di Giovanni, A., Ding, Q., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., Fan, R. R., Fan, Y. Z., Fang, F., Fang, K., Feng, C. Q., Feng, L., Frieden, J. M., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, L. Y., Jiang, Y. Z., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, W. H., Li, W. L., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Putti-Garcia, E., Qiao, R., Rao, J. N., Ruina, A., Sarkar, R., Savina, P., Serpolla, A., Shangguan, Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, H. R., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, J. Z., Wang, L. G., Wang, S., Wang, S. X., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, S. S., Wu, X., Xia, Z. Q., Xu, H. T., Xu, J., Xu, Z. H., Xu, Z. L., Xu, E. H., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, S. X., Zhang, W. Z., Zhang, Yan, Zhang, Yi, Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.

Subjects
High Energy Physics - Experiment
Abstract

Precise direct cosmic-ray (CR) measurements provide an important probe to study the energetic particle sources in our Galaxy, and the interstellar environment through which these particles propagate. Uncertainties on hadronic models, ion-nucleon cross sections in particular, are currently the limiting factor towards obtaining more accurate CR ion flux measurements with calorimetric space-based experiments. We present an energy-dependent measurement of the inelastic cross section of protons and helium-4 nuclei (alpha particles) on a Bi$_4$Ge$_3$O$_{12}$ target, using 88 months of data collected by the DAMPE space mission. The kinetic energy range per nucleon of the measurement points ranges from 18 GeV to 9 TeV for protons, and from 5 GeV/n to 3 TeV/n for helium-4 nuclei. Our results lead to a significant improvement of the CR flux normalisation. In the case of helium-4, these results correspond to the first cross section measurements on a heavy target material at energies above 10 GeV/n., Comment: Published in PRD

Published
2024
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3. Ultrafast measurement of field-particle energy transfer during chorus emissions in space

Author

Liu, C. M., Zhao, B. N., Cao, J. B., Pollock, C. J., Russell, C. T., Liu, Y. Y., Xing, X. N., Linqvist, P. A., and Burch, J. L.

Subjects
Physics - Space Physics
Abstract

Chorus is one of the strongest electromagnetic emissions naturally occurring in space, and can cause hazardous radiations to humans and satellites1-3. Although chorus has attracted extreme interest and been intensively studied for decades4-7, its generation and evolution remain highly debated, due to the complexity of the underlying physics and the limited capacity of previous spacecraft missions7. Chorus has also been believed to be governed by planetary magnetic dipolar fields5,7. Contrary to such conventional expectation, here we report unexpected observations of chorus in the terrestrial neutral sheet where magnetic dipolar effect is absent. Using unprecedentedly high-cadence data from the Magnetospheric Multiscale Mission, we present the first, ultrafast measurements of the wave dispersion relation and electron three-dimensional distributions within the waves, showing smoking-gun evidences for chorus-electron interactions and development of electron holes in the wave phase space. We estimate field-particle energy transfer inside the waves and find that the waves were extracting energy from local thermal electrons, in line with the wave positive growth rate derived from instability analysis. Our observations, opening new pathways for resolving long-standing controversies regarding the chorus emissions, are crucial for understanding nonlinear energy transport ubiquitously observed in space and astrophysical environments., Comment: under review; comments and suggestions are welcomed

Published
2024

10. Measurement of the cosmic p+He energy spectrum from 50 GeV to 0.5 PeV with the DAMPE space mission

Author

DAMPE Collaboration, Alemanno, F., Altomare, C., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cagnoli, I., Cai, M. S., Casilli, E., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Coppin, P., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., De Benedittis, A., De Mitri, I., de Palma, F., Deliyergiyev, M., Di Giovanni, A., Di Santo, M., Ding, Q., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., Fan, R. R., Fan, Y. Z., Fang, F., Fang, K., Feng, C. Q., Feng, L., Alonso, M. Fernandez, Frieden, J. M., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, L. Y., Jiang, Y. Z., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, W. H., Li, W. L., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Salinas, M. Muñoz, Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Putti-Garcia, E., Qiao, R., Rao, J. N., Ruina, A., Shangguan, Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, H. R., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, J. Z., Wang, L. G., Wang, S., Wang, S. X., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xia, Z. Q., Xu, H. T., Xu, J., Xu, Z. H., Xu, Z. L., Xu, E. H., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, S. X., Zhang, W. Z., Zhang, Yan, Zhang, Yi, Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

Recent observations of the light component of the cosmic-ray spectrum have revealed unexpected features that motivate further and more precise measurements up to the highest energies. The Dark Matter Particle Explorer is a satellite-based cosmic-ray experiment that has been operational since December 2015, continuously collecting data on high-energy cosmic particles with very good statistics, energy resolution, and particle identification capabilities. In this work, the latest measurements of the energy spectrum of proton+helium in the energy range from 46 GeV to 464 TeV are presented. Among the most distinctive features of the spectrum, a spectral hardening at 600 GeV has been observed, along with a softening at 29 TeV measured with a 6.6{\sigma} significance. Moreover, the detector features and the analysis approach allowed for the extension of the spectral measurement up to the sub-PeV region. Even if with small statistical significance due to the low number of events, data suggest a new spectral hardening at about 150 TeV., Comment: Published on PRD

Published
2023
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11. Search for relativistic fractionally charged particles in space

Author

DAMPE Collaboration, Alemanno, F., Altomare, C., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cai, M. S., Casilli, E., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., De-Benedittis, A., De Mitri, I., de Palma, F., Deliyergiyev, M., Di Giovanni, A., Di Santo, M., Ding, Q., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Fang, K., Feng, C. Q., Feng, L., Alonso, M. F., Frieden, J. M., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, L. Y., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, W. L., Li, W. H., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Salinas, M. M., Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Qiao, R., Rao, J. N., Ruina, A., Shangguan, Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, H. R., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, J. Z., Wang, L. G., Wang, S., Wang, S. X., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xia, Z. Q., Xu, E. H., Xu, H. T., Xu, J., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, S. X., Zhang, W. Z., Zhang, Yan, Zhang, Yi., Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology, Physics - Space Physics
Abstract

More than a century after the performance of the oil drop experiment, the possible existence of fractionally charged particles FCP still remains unsettled. The search for FCPs is crucial for some extensions of the Standard Model in particle physics. Most of the previously conducted searches for FCPs in cosmic rays were based on experiments underground or at high altitudes. However, there have been few searches for FCPs in cosmic rays carried out in orbit other than AMS-01 flown by a space shuttle and BESS by a balloon at the top of the atmosphere. In this study, we conduct an FCP search in space based on on-orbit data obtained using the DArk Matter Particle Explorer (DAMPE) satellite over a period of five years. Unlike underground experiments, which require an FCP energy of the order of hundreds of GeV, our FCP search starts at only a few GeV. An upper limit of $6.2\times 10^{-10}~~\mathrm{cm^{-2}sr^{-1} s^{-1}}$ is obtained for the flux. Our results demonstrate that DAMPE exhibits higher sensitivity than experiments of similar types by three orders of magnitude that more stringently restricts the conditions for the existence of FCP in primary cosmic rays., Comment: 19 pages, 6 figures, accepted by PRD

Published
2022
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13. Characteristics of Interplanetary Discontinuities in the Inner Heliosphere Revealed by Parker Solar Probe

Author

Liu, Y. Y., Fu, H. S., Cao, J. B., Liu, C. M., Wang, Z., Guo, Z. Z., Xu, Y., Bale, S. D., and Kasper, J. C.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Space Physics
Abstract

We present a statistical analysis for the characteristics and spatial evolution of the interplanetary discontinuities (IDs) in the solar wind, from 0.13 to 0.9 au, by using the Parker Solar Probe measurements on Orbits 4 and 5. 3948 IDs have been collected, including 2511 rotational discontinuities (RDs) and 557 tangential discontinuities (TDs), with the remnant unidentified. The statistical results show that (1) the ID occurrence rate decreases from 200 events/day at 0.13 au to 1 events/day at 0.9 au, following a spatial scaling r-2.00, (2) the RD to TD ratio decreases quickly with the heliocentric distance, from 8 at r<0.3 au to 1 at r>0.4 au, (3) the magnetic field tends to rotate across the IDs, 45{\deg} for TDs and 30{\deg} for RDs in the pristine solar wind within 0.3 au, (4) a special subgroup of RDs exist within 0.3 au, characterized by small field rotation angles and parallel or antiparallel propagations to the background magnetic fields, (5) the TD thicknesses normalized by local ion inertial lengths (di) show no clear spatial scaling and generally range from 5 to 35 di, and the normalized RD thicknesses follow r-1.09 spatial scaling, (6) the outward (anti-sunward) propagating RDs predominate in all RDs, with the propagation speeds in the plasma rest frame proportional to r-1.03. This work could improve our understandings for the ID characteristics and evolutions and shed light on the study of the turbulent environment in the pristine solar wind., Comment: Accepted by ApJS

Published
2021
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14. Measurement of the cosmic ray helium energy spectrum from 70 GeV to 80 TeV with the DAMPE space mission

Author

Alemanno, F., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cai, M. S., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., D'Amone, A., De Benedittis, A., De Mitri, I., de Palma, F., Deliyergiyev, M., Di Santo, M., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, K., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Guo, X. L., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, S., Li, W. L., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Qiao, R., Rao, J. N., Ruina, A., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, H., Wang, J. Z., Wang, L. G., Wang, S., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wen, S. C., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xia, Z. Q., Xu, H. T., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the DArk Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of $4.3\sigma$. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out., Comment: 11 pages, 13 figures, published in Phys. Rev. Lett. Add one more digit for first three columns in Table S2

Published
2021
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15. First observation of magnetic flux rope inside electron diffusion region

Author

Chen, Z. Z., Fu, H. S., Wang, Z., Guo, Z. Z., Xu, Y., and Liu, C. M.

Subjects
Physics - Space Physics, Physics - Plasma Physics
Abstract

Magnrtic flux ropes (MFRs) play a crucial role during magnetic reconnection. They are believed to be primarily generated by tearing mode instabilities in the electron diffusion region (EDR). However, they have never been observed inside the EDR. Here, we present the first observation of an MFR inside an EDR. The bifurcated non-force-free MFR, with a width of 27.5de in the L direction and 4.8de in the N direction, was moving away from the X-line. Inside the MFR, strong energy dissipation was detected. The MFR can modulate the electric field in the EDR. We reconstructed magnetic topology of the electron-scale MFR. Our study promotes understanding of MRFs' initial state and its role in electron-scale processes during magnetic reconnection., Comment: 27 pages, 4 figures

Published
2020
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16. Response of the BGO Calorimeter to Cosmic Ray Nuclei in the DAMPE Experiment on Orbit

Author

Dai, H. T., Zhang, Y. L., Zang, J. J., Zhang, Z. Y., Wei, Y. F., Wu, L. B., Liu, C. M., Luo, C. N., Kyratzis, D., De Benedittis, A., Zhao, C., Wang, Y., Jiang, P. C., Wang, Y. Z., Zhao, Y. Z., Wang, X. L., Xu, Z. Z., and Huang, G. S.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

This paper is about a study on the response of the BGO calorimeter of DAMPE experiment. Four elements in Cosmic Ray nuclei are used as sources for this analysis. A feature resulting from the geomagnetic cutoff exhibits in the energy spectrum, both in simulated and reconstructed data, and is compared between them.

Published
2020
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18. Measurement of the cosmic-ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

Author

An, Q., Asfandiyarov, R., Azzarello, P., Bernardini, P., Bi, X. J., Cai, M. S., Chang, J., Chen, D. Y., Chen, H. F., Chen, J. L., Chen, W., Cui, M. Y., Cui, T. S., Dai, H. T., D'Amone, A., De Benedittis, A., De Mitri, I., Di Santo, M., Ding, M., Dong, T. K., Dong, Y. F., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gallo, V., Gan, F. J., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Guo, X. L., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, W., Jin, X., Kong, J., Lei, S. J., Li, S., Li, W. L., Li, X., Li, X. Q., Li, Y., Liang, Y. F., Liang, Y. M., Liao, N. H., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, S. Y., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Peng, W. X., Peng, X. Y., Qiao, R., Rao, J. N., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Song, J. X., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Vitillo, S., Wang, C., Wang, H., Wang, H. Y., Wang, J. Z., Wang, L. G., Wang, Q., Wang, S., Wang, X. H., Wang, X. L., Wang, Y. F., Wang, Y. P., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wen, S. C., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xi, K., Xia, Z. Q., Xu, H. T., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yang, Z. L., Yao, H. J., Yu, Y. H., Yuan, Q., Yue, C., Zang, J. J., Zhang, F., Zhang, J. Y., Zhang, J. Z., Zhang, P. F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, H., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., Zhou, Y., Zhu, X., Zhu, Y., and Zimmer, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with two and a half years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time an experiment directly measures the cosmic ray protons up to ~100 TeV with a high statistics. The measured spectrum confirms the spectral hardening found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee, and sheds new light on the origin of Galactic cosmic rays., Comment: 37 pages, 5 figures, published in Science Advances

Published
2019
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19. The on-orbit calibration of DArk Matter Particle Explorer

Author

Ambrosi, G., An, Q., Asfandiyarov, R., Azzarello, P., Bernardini, P., Cai, M. S., Caragiulo, M., Chang, J., Chen, D. Y., Chen, H. F., Chen, J. L., Chen, W., Cui, M. Y., Cui, T. S., Dai, H. T., D'Amone, A., De Benedittis, A., De Mitri, I., Ding, M., Di Santo, M., Dong, J. N., Dong, T. K., Dong, Y. F., Dong, Z. X., Droz, D., Duan, K. K., Duan, J. L., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gallo, V., Gan, F. J., Gao, M., Gao, S. S., Gargano, F., Garrappa, S., Gong, K., Gong, Y. Z., Guo, J. H., Hu, Y. M., Huang, G. S., Huang, Y. Y., Ionica, M., Jiang, D., Jiang, W., Jin, X., Kong, J., Lei, S. J., Li, S., Li, X., Li, W. L., Li, Y., Liang, Y. F., Liang, Y. M., Liao, N. H., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Ma, M., Ma, P. X., Ma, S. Y., Ma, T., Ma, X. Q., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Peng, X. Y., Peng, W. X., Qiao, R., Rao, J. N., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Song, J. X., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tian, X. B., Tykhonov, A., Vitillo, S., Wang, C., Wang, H., Wang, H. Y., Wang, J. Z., Wang, L. G., Wang, Q., Wang, S., Wang, X. H., Wang, X. L., Wang, Y. F., Wang, Y. P., Wang, Y. Z., Wang, Z. M., Wen, S. C., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xi, K., Xia, Z. Q., Xin, Y. L., Xu, H. T., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yang, Z. L., Yao, H. J., Yu, Y. H., Yuan, Q., Yue, C., Zang, J. J., Zhang, D. L., Zhang, F., Zhang, J. B., Zhang, J. Y., Zhang, J. Z., Zhang, L., Zhang, P. F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. Q., Zhang, Y. L., Zhang, Y. P., Zhang, Z., Zhang, Z. Y., Zhao, H., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., Zhou, Y., Zhu, X., Zhu, Y., and Zimmer, S.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

The DArk Matter Particle Explorer (DAMPE), a satellite-based cosmic ray and gamma-ray detector, was launched on December 17, 2015, and began its on-orbit operation on December 24, 2015. In this work we document the on-orbit calibration procedures used by DAMPE and report the calibration results of the Plastic Scintillator strip Detector (PSD), the Silicon-Tungsten tracKer-converter (STK), the BGO imaging calorimeter (BGO), and the Neutron Detector (NUD). The results are obtained using Galactic cosmic rays, bright known GeV gamma-ray sources, and charge injection into the front-end electronics of each sub-detector. The determination of the boundary of the South Atlantic Anomaly (SAA), the measurement of the live time, and the alignments of the detectors are also introduced. The calibration results demonstrate the stability of the detectors in almost two years of the on-orbit operation.

Published
2019
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26. Autogenous Electron Acceleration by Ion Flow Vortex in Space Plasmas.

Author

Liu, C. M., Cao, J. B., Liu, Y. Y., Kronberg, E. A., Xing, X. N., Zhao, B. N., and Daly, P. W.

Subjects
*ASTROPHYSICAL jets, *PLASMA flow, *PLASMA astrophysics, *SPACE plasmas, *ELECTRON accelerators
Abstract

Plasma flow vortexes are ubiquitous in space and astrophysical settings and play a vital role in energy and mass transport, contributing to formation of stars and planets, launching and dissipation of astrophysical jets, and coupling between planetary magnetospheres and ionospheres. Here we present in situ observations showing that energetic electrons with energies up to 250 keV can be directly generated inside an ion flow vortex with finite spatial scale. The electron acceleration is achieved by establishment of Fermi acceleration trap and parallel electrostatic potential within the flow vortex, leading to dramatic enhancement of energetic electron flux by at least 1 order of magnitude. The accelerated electrons can drive mass and energy transport along local magnetic field lines and serve as a free energy source for broadband electrostatic emissions. Our observations, suggesting that the ion flow vortex can serve as novel electron accelerators, can be fundamentally important for understanding energetic phenomena in the cosmos, such as nonthermal emissions near astrophysical jets and killer electrons in geospace. [ABSTRACT FROM AUTHOR]

Published
2025
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41. Trap-induced electrical degradation in edge-termination-hardened NiO/β-Ga2O3 heterojunction under 10 MeV fluence-dependent proton irradiations.

Author

Zhang, Z. L., Sun, N., Wang, T. Q., Zhou, F., Liu, C. M., Qi, C. H., Ma, G. L., Zhang, Y. Q., Li, H. Y., Lei, Z. F., Ye, J. D., Lu, H., Huo, M. X., and Xiao, L. Y.

Abstract

Ultrawide bandgap beta-phase gallium oxide (β-Ga2O3) power devices have great potential in irradiation applications, yet the instability of their electrical performance induced by irradiation remains under investigation. This work examines the degradation of electrical performance in edge-termination-hardened nickel oxide (NiO)/β-Ga2O3 heterojunction p–n diodes (ETH-HJDs) subject to 10 MeV proton irradiation across a wide fluence range of 1011–1013 p/cm2. The results reveal interface and bulk trap-induced degradation with intriguing non-monotonic variations in forward conduction and reverse leakage currents—initially increasing and then decreasing with increased irradiation fluences. This abnormal phenomenon is unlikely due to irradiation-induced edge damage as the ETH design was implemented. Forward I–V curve modeling showcases an aggravated series resistance effect after irradiation, with the ideality factor rising from 1.07 to 1.24, indicating deteriorated interface properties. Capacitance–voltage (C–V) characterizations suggest that bulk traps caused by irradiation impact the carrier removal effect, evidenced by a carrier removal rate of 1070 cm−1 at a high proton fluence of 1 × 1013 p/cm2. Furthermore, deep-level transient spectroscopy reveals four distinct types of traps distributed at the interface or within Ga2O3 bulk contributing to the device leakage. These findings offer critical insights into the instability of electrical characteristics in high-performance NiO/β-Ga2O3 HJDs under proton irradiation. [ABSTRACT FROM AUTHOR]

Published
2024
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42. Two‐Step Electron Acceleration During a Flux Rope Crossing of Earth's Bow Shock.

Author

Hu, D. K., Liu, Y. Y., Cao, J. B., and Liu, C. M.

Subjects
PARTICLE acceleration, INTERPLANETARY magnetic fields, FLUX pinning, ACCELERATION (Mechanics), MAGNETIC declination
Abstract

The generation of cosmic ray particles with ultra‐relativistic energies is a crucial issue in astrophysical and space physics. Shocks have been acknowledged as efficient accelerators in the universe which can produce energetic particles through a variety of mechanisms, such as diffusive shock acceleration (DSA), shock surfing acceleration (SSA) and shock drift acceleration (SDA). Using the data set obtained by the Magnetospheric Multiscale mission, we report an unusually sharp enhancement of energetic electron flux in the upstream region of Earth's bow shock, associated with a bipolar variation of the interplanetary magnetic field. To explain these observations, we propose a two‐step acceleration scenario where electrons trapped in a flux rope (FR) first undergo head‐on collisions and are further accelerated by FR contraction as the FR crosses the shock. Such a scenario can well explain the spacecraft observations. This work can improve our understanding of particle acceleration processes at shocks. Plain Language Summary: The cosmic ray comprises ions and electrons with energies up to 1,020 eV and thus its generation mechanism is an important issue. A conventional theory known as diffusive shock acceleration is a promising candidate but it needs seed electrons with sufficient initial energies. How these electrons are generated is still unclear. In this study, we report an unusually sharp enhancement of energetic electron flux with a large variation of magnetic field direction in the upstream region of Earth's bow shock, and propose a two‐step acceleration scenario to explain the spacecraft measurements. Electrons first gain energies from the head‐on collisions with the bow shock, and then bounce between the two ends of a circular magnetic field of shrinkage, analogous to a ball reflecting between two converging walls. This scenario has been mathematically confirmed and shows good agreement with the spacecraft measurements. Key Points: Efficient electron acceleration is observed when a flux rope collides with the Earth's bow shockElectrons trapped in the flux rope are successively accelerated by the head‐on reflection at shock front and the flux rope contractionThis two‐step acceleration scenario is mathematically reproduced and fit the spacecraft observations well [ABSTRACT FROM AUTHOR]

Published
2024
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43. Energy Conversion in the Dip Region Preceding Dipolarization Front.

Author

Zhao, B. N., Liu, C. M., Cao, J. B., Liu, Y. Y., and Xing, X. N.

Subjects
*ENERGY conversion, *ELECTRIC currents, *PLASMA jets, *SPACE environment, *MAGNETIC fields, *FRONTS (Meteorology), *ELECTRIC fields
Abstract

Dipolarization fronts (DFs), characterized by sharp increases in the northward magnetic field and usually preceded by magnetic dips, are suggested to play an important role in energy conversion and transport in the magnetotail. It has been documented that strong energy conversion typically develops right at the fronts. Here we present spacecraft observations of electron‐scale energy conversion (EEC) developed inside the dip region ahead of a DF, by using high‐cadence data from the Magnetospheric Multiscale Mission. The EEC, with magnitude comparable to that at the front, is primarily driven by ion current and electron‐scale electric field. The electric field inside the dip is provided by electrostatic waves fed by lower hybrid drift instability, which experiences temporal decaying. Such decaying leads to nonhomogeneity of EEC along the dawn‐dusk direction. These results, uncovering a new channel for DF‐driven energy conversion, can provide important insights into understanding energy transport in the magnetotail. Plain Language Summary: Space weather is determined by earthward transport of energy and mass in the magnetosphere. In the magnetotail, such transport is usually associated with dipolarization fronts embedded inside high‐speed plasma jets, which are characterized by a sharp enhancement of the northward component of the magnetic field and serve as the leading boundaries of plasma jets. Statistical studies reveal that a small decrease in the magnetic field often occurs ahead of the fronts, which is dubbed as a magnetic dip. Dipolarization fronts have been suggested to play a key role in the energy conversion chain in the magnetotail, and the energy conversion typically happens right in the front region where strong currents and electric fields usually develop. In this research, we find that in addition to the front region, the dip preceding the fronts can also host strong energy conversion. Our results help further understand energy conversion in the terrestrial magnetotail. Key Points: Electron‐scale energy conversion (EEC) is observed for the first time in the magnetic dip ahead of a dipolarization frontThe EEC, with magnitude comparable to that at the front, is primarily driven by ion current and electron‐scale motional electric fieldThe EEC electric field is induced by a decaying lower hybrid drift instability which may cause temporal damping of the EEC [ABSTRACT FROM AUTHOR]

Published
2024
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44. Extended Energy Conversion and Electron Acceleration Behind Dipolarization Front.

Author

Xing, X. N., Liu, C. M., Liu, Y. Y., and Zhao, B. N.

Subjects
ENERGY conversion, PLASMA jets, ELECTRONS, TRADITIONAL knowledge, ENERGY transfer
Abstract

Energy transfer and transport in the terrestrial magnetotails are primarily driven by dipolarization fronts (DFs) embedded inside plasma jets. The DF‐driven energy transfer has hitherto been believed to occur locally at the fronts. Different from the traditional knowledge, here we present the first observation of persistent energy conversion extended far behind a DF. The persistent energy conversion, which was dominated by energy loads and mainly contributed by electron currents, developed inside a turbulent, decaying flux pileup region (FPR), nearly 10 dDF (DF's thickness) behind the DF. The energy transfer chain may be initiated by interaction between the ion flow and ambient plasmas and closed by electron dynamics, leading to electron acceleration perpendicular to magnetic field. These results highlight that electron physics in turbulent FPRs plays a crucial role in the energy transport in the planetary magnetospheres. Key Points: Persistent energy conversion extended far (∼10 dDF) behind a dipolarization front is presentedThe persistent energy conversion was developed inside a decaying flux pileup region and driven by electron currentsThe persistent energy conversion was related to electron acceleration perpendicular to local magnetic field [ABSTRACT FROM AUTHOR]

Published
2024
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46. The application of 4S atrial fibrillation scheme in predicting atrial arrhythmia recurrence after catheter ablation

Author

Kuo, L, primary, Chao, T F, additional, Chang, S L, additional, Lin, Y J, additional, Chung, F P, additional, Lo, L W, additional, Hu, Y F, additional, Duan, T C, additional, Liao, J N, additional, Chang, T Y, additional, Lin, C Y, additional, Liu, C M, additional, Liu, S H, additional, Wu, C I, additional, and Chen, S A, additional

Published
2023
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