A possible driver of precipitation of magnetospheric energetic electrons in the high-latitude atmosphere is represented by electromagnetic ion-cyclotron (EMIC) magnetospheric waves. The precipitating particles produce variations, by collision, in the ionized component of the atmosphere, altering its chemistry and electrical conductivity, with a significant impact on the atmospheric processes. In this framework, it would be significant to find experimental evidence of a correspondence between ionospheric electron density irregularities and the occurrence of Ultra-Low-Frequency (ULF) Pc1 geomagnetic pulsations, i.e., the ground signatures of EMIC waves, at high latitudes. In this work, we face this subject by considering a specific case study occurred on 22 February 2007 during quiet magnetospheric conditions. The study is based on the analysis of simultaneous ULF geomagnetic field and Total Electron Content (TEC) measurements recorded at Mario Zucchelli Station in Antarctica. We show that Pc1 pulsations occur in correspondence to solar wind pressure increases and that, at the same time, the ionosphere is characterized by the presence of ionospheric irregularities. We suggest that a possible link between the Pc1 activity and the ionospheric irregularities may be energetic electron precipitations, driven by EMIC waves generated in the compressed magnetosphere, which produce density variations in the ionized component of the atmosphere.

中文翻译：

---

Pc1活动与极纬度电离层不规则性之间对应关系的案例研究

高纬度大气中磁层高能电子沉淀的可能驱动因素是电磁离子回旋加速器 (EMIC) 磁层波。沉淀粒子通过碰撞在大气的电离成分中产生变化，改变其化学性质和电导率，对大气过程产生重大影响。在这个框架中，找到电离层电子密度不规则性与超低频 (ULF) Pc1 地磁脉动（即高纬度地区 EMIC 波的地面特征）的发生之间的对应关系的实验证据将具有重要意义。在这项工作中，我们通过考虑 2007 年 2 月 22 日在安静磁层条件下发生的特定案例研究来面对这个主题。该研究基于对南极洲 Mario Zucchelli 站记录的同步超低频地磁场和总电子含量 (TEC) 测量值的分析。我们表明 Pc1 脉动的发生与太阳风压的增加相对应，同时，电离层的特点是存在电离层不规则性。我们认为，Pc1 活动与电离层不规则性之间可能存在联系，这可能是由压缩磁层中产生的 EMIC 波驱动的高能电子沉淀，这会导致大气电离成分的密度变化。我们表明 Pc1 脉动的发生与太阳风压的增加相对应，同时，电离层的特点是存在电离层不规则性。我们认为，Pc1 活动与电离层不规则性之间可能存在联系，这可能是由压缩磁层中产生的 EMIC 波驱动的高能电子沉淀，这会导致大气电离成分的密度变化。我们表明 Pc1 脉动的发生与太阳风压的增加相对应，同时，电离层的特点是存在电离层不规则性。我们认为，Pc1 活动与电离层不规则性之间可能存在联系，这可能是由压缩磁层中产生的 EMIC 波驱动的高能电子沉淀，这会导致大气电离成分的密度变化。