The local magnetic field in a Penning-Malmberg trap is found by measuring the temperatures that result when electron plasmas are illuminated by microwaves pulses. Multiple heating resonances are observed as the pulse frequencies are swept. The many resonances are due to electron bounce and plasma rotation sidebands. The heating peak corresponding to the cyclotron frequency resonance is identified to determine the magnetic field. A new method for quickly preparing low density electron plasmas for destructive temperature measurements enables a rapid and automated scan of microwave frequencies. This technique can determine the magnetic field to high precision, obtaining an absolute accuracy better than $1\,\mathrm{ppm}$, and a relative precision of $26\,\mathrm{ppb}$. One important application is in situ magnetometry for antihydrogen-based tests of charge-parity-time symmetry and of the weak equivalence principle

中文翻译：

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带有等离子体库的电子回旋共振 (ECR) 磁力测定法

Penning-Malmberg 陷阱中的局部磁场是通过测量微波脉冲照射电子等离子体时产生的温度来发现的。当扫描脉冲频率时观察到多个加热共振。许多共振是由于电子反弹和等离子体旋转边带。识别与回旋频率共振对应的加热峰以确定磁场。一种快速制备用于破坏性温度测量的低密度电子等离子体的新方法可以快速自动扫描微波频率。该技术可以高精度地确定磁场，获得优于$1\,\mathrm{ppm}$的绝对精度，以及$26\,\mathrm{ppb}$的相对精度。