dorsal/arxiv
View SchemaMeasurement of electron sheath thickness and collection region of electric probe using laser photodetachment signals
| Authors | Shin Kajita, Shinichiro Kado, Atsushi Okamoto, Taiichi Shikama, Yohei Iida, Daisuke Yamasaki, Satoru Tanaka |
|---|---|
| Categories | |
| ArXiv ID | physics/0410187 |
| URL | https://arxiv.org/abs/physics/0410187 |
Abstract
A new type of laser photodetachment (LPD) technique has been developed for the measurement of electron sheath thickness around an electrostatic probe and for the measurement of the length of collection region of photodetached electrons (PDE). When a thickness of the sheath formed around an electrostatic probe is thicker than about 0.1 mm, modification of the temporal evolution of the LPD signal is observed. By making use of the modification, we evaluated sheath thickness around a cylindrical probe in the existence of the magnetic field of 15 mT. It was found that the thickness of electron sheath along the magnetic field was comparable to the calculated plane-parallel Child-Langmuir sheath thickness when the probe-bias voltage was high. Furthermore, by inserting a small screening object in the laser beam channel, we can measure the sheath thickness from the modification of LPD signal. From the variation of the signal intensity as scanning the screening object perpendicular to the laser beam channel, we can observe the collection region of photodetached electrons, because this procedure changes the relative displacement between shadow and the probe electrode.
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"date_modified": "2026-03-02T18:00:53.791000Z",
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"abstract": "A new type of laser photodetachment (LPD) technique has been developed for\nthe measurement of electron sheath thickness around an electrostatic probe and\nfor the measurement of the length of collection region of photodetached\nelectrons (PDE). When a thickness of the sheath formed around an electrostatic\nprobe is thicker than about 0.1 mm, modification of the temporal evolution of\nthe LPD signal is observed. By making use of the modification, we evaluated\nsheath thickness around a cylindrical probe in the existence of the magnetic\nfield of 15 mT. It was found that the thickness of electron sheath along the\nmagnetic field was comparable to the calculated plane-parallel Child-Langmuir\nsheath thickness when the probe-bias voltage was high. Furthermore, by\ninserting a small screening object in the laser beam channel, we can measure\nthe sheath thickness from the modification of LPD signal. From the variation of\nthe signal intensity as scanning the screening object perpendicular to the\nlaser beam channel, we can observe the collection region of photodetached\nelectrons, because this procedure changes the relative displacement between\nshadow and the probe electrode.",
"arxiv_id": "physics/0410187",
"authors": [
"Shin Kajita",
"Shinichiro Kado",
"Atsushi Okamoto",
"Taiichi Shikama",
"Yohei Iida",
"Daisuke Yamasaki",
"Satoru Tanaka"
],
"categories": [
"physics.plasm-ph"
],
"title": "Measurement of electron sheath thickness and collection region of electric probe using laser photodetachment signals",
"url": "https://arxiv.org/abs/physics/0410187"
},
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