Prompt penetration electric fields were detected during the intense geomagnetic storm on 22 June, 2015 by the HF Doppler sounders at middle and low latitudes; Prague (Czech Republic), Iitate, Oarai, Onna (Japan), and Zhongli (Republic of China). The storm was initiated by the storm sudden commencement (SC) at 1833 UT, immediately followed by the main phase with the minimum SYM-H of − 139 nT at 2017 UT. The convection electric field was found to be up to 5.1 mV/m at low latitudes, which is enough to cause ionospheric disturbances such as the enhancement of the total electron content, equatorial ionization anomaly and so on. The electric fields of the SC and main phase are westward in the night (0330 MLT), while eastward in the evening (1930 MLT). The main phase electric field intensified the eastward equatorial electrojets (EEJ) at Huancayo in South America on the dayside (1330 MLT) and the westward EEJ on the nightside at Guam in the western Pacific (0330 MLT) and Tirunelveli in India (00 MLT). The eastward direction of the evening-time electric field agrees with a feature of the evening anomaly of the penetration electric field, while the intensity is suppressed because of the sunlit condition in the evening in the summer solstice. The sudden northward turning of the interplanetary magnetic field (IMF) caused a transition from the main phase to the recovery phase, when the EEJ turned into the counterelectrojet (CEJ). It was found that the HF Doppler sounders detected an impulsive eastward overshielding electric field at 2005 UT on the nightside during the northward IMF-driven CEJ with the duration of 17 min and intensity of 8.0 mV/m at Iitate (0500 MLT) and 11.8 mV/m at Prague (2130 MLT). The impulsive overshielding electric field was accompanied by the anti-sunward plasma flows at middle latitude (50°–60° GML) equatorward of the dusk sunward convection as observed with SuperDARN, which signifies intensification of the Region-2 field-aligned currents at the flow reversal. Substorm signatures are identified with intensified westward auroral electrojet and magnetic dipolarization as detected by the geosynchronous orbit satellite, ETS-VIII. Consequently, the stormtime substorm may provide strong overshielding electric fields to the middle latitude ionosphere on the nightside.

中文翻译：

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2015 年 6 月 22 日地磁风暴期间在中低纬度观测到的穿透电场

2015 年 6 月 22 日强地磁暴期间，中、低纬度 HF 多普勒测深仪探测到快速穿透电场；布拉格（捷克共和国）、饭馆、大洗、恩纳（日本）和中坜（中华民国）。风暴由 1833 UT 的风暴突然开始 (SC) 引发，紧随其后的是主相位，在 2017 UT 的最小 SYM-H 为 − 139 nT。发现低纬度对流电场高达5.1 mV/m，足以引起总电子含量增加、赤道电离异常等电离层扰动。SC和主相的电场在夜间（0330 MLT）向西，而在晚上（1930 MLT）向东。主相电场增强了南美洲万卡约日侧（1330 MLT）的东向赤道电射流（EEJ）和西太平洋关岛（0330 MLT）和印度蒂鲁内尔维利（00 MLT）夜侧的西向EEJ . 晚间电场向东方向符合穿透电场晚间异常的特征，但由于夏至傍晚的阳光照射，强度受到抑制。当 EEJ 变成反电射流 (CEJ) 时，行星际磁场 (IMF) 突然向北转向导致从主阶段过渡到恢复阶段。发现高频多普勒测深仪在北向IMF驱动的CEJ期间在2005 UT夜侧探测到一个脉冲东向过屏蔽电场，持续时间为17 min，在Iitate (0500 MLT)和11.8 mV的强度为8.0 mV/m /m 在布拉格 (2130 MLT)。如 SuperDARN 所观察到的，脉冲过屏蔽电场伴随着中纬度（GML 50°–60° GML）赤道的反向日等离子体流，如 SuperDARN 所观察到的那样，这表明区域 2 场对齐电流在流量逆转。地球同步轨道卫星 ETS-VIII 检测到的亚暴特征可以通过加强的西向极光电喷射和磁偶极化来识别。最后，