Plazma parametrlari

Plazma parametrlari plazmaning turli xususiyatlarini, elektromagnit kuchlarga birgalikda javob beradigan zaryadlangan zarrachalarning elektr o'tkazuvchan to'plamini belgilaydi. Plazma odatda neytral gazga o'xshash bulutlar yoki zaryadlangan ion nurlari shaklida bo'ladi, lekin chang va donalarni ham o'z ichiga olishi mumkin.^[1] Bunday zarrachalar sistemalarining harakatini statistik jihatdan o'rganish mumkin.^[2]

Plazmaning asosiy parametrlari

Elektronvoltlarda bo'lgan energiya va haroratdan tashqari barcha miqdorlar Gauss (cgs) birliklarida. Ion massasi proton massasining birliklarida ifodalanadi $\mu =m_{i}/m_{p}$ va $Z$ elementar zaryad birliklarida ion zaryadi $e$ (to'liq ionlangan atom holatida, $Z$ tegishli atom raqamiga teng). Qo'llaniladigan boshqa fizik miqdorlar: Boltsman doimiysi ( $k$ ), yorug'lik tezligi ( $c$ ) va Kulon logarifmi.

O'lchamsiz

"Probirkadagi quyosh". Farnsvort-Xirsh Fusori "yulduzli rejim" deb ataladigan rejimda ishlayotganda, u ichki to'rning bo'shliqlaridan chiqadigan porlayotgan plazma "nurlari" bilan tavsiflanadi.

Debay sferasidagi zarralar soni
$\left({\frac {4\pi }{3}}\right)n\lambda _{D}^{3}\approx 1.72\times 10^{9}\,\left({\frac {T^{3}}{n}}\right)^{\frac {1}{2}}$
Alfven tezligi yorug'lik tezligiga nisbati
${\frac {v_{A}}{c}}\approx 7.28\,{\frac {B}{\left(\mu n_{i}\right)^{\frac {1}{2}}}}$
elektron plazma chastotasi gyrofrequency nisbati
${\frac {\omega _{pe}}{\omega _{ce}}}\approx 3.21\times 10^{-3}\,{\frac {{n_{e}}^{\frac {1}{2}}}{B}}$
ion plazma chastotasi gyrofrequency nisbati
${\frac {\omega _{pi}}{\omega _{ci}}}\approx 0.137\,{\frac {\left(\mu n_{i}\right)^{\frac {1}{2}}}{B}}$
termal bosimning magnit bosimga nisbati yoki beta, b
$\beta ={\frac {8\pi nkT}{B^{2}}}\approx 4.03\times 10^{-11}\,{\frac {nT}{B^{2}}}$
magnit maydon energiyasining ionning dam olish energiyasiga nisbati
${\frac {B^{2}}{8\pi n_{i}m_{i}c^{2}}}\approx 26.5\,{\frac {B^{2}}{\mu n_{i}}}$

To'qnashuv

To'qmashuvlarni o'rganishda to'qnashuv o'lchovsiz parametr bo'lib, u elektron-ion to'qnashuv chastotasining orbita chastotasiga nisbatini ifodalaydi.

Plazma to'qnashuvi $\nu ^{*}$ ^[3]^[4] sifatida aniqlanadi

\nu ^{*}=\nu _{\mathrm {ei} }\,{\sqrt {\frac {m_{\mathrm {e} }}{k_{\mathrm {B} }T_{\mathrm {e} }}}}\,{\frac {1}{\epsilon ^{\frac {3}{2}}}}\,qR,

bu yerda $\nu _{\mathrm {ei} }$ elektron-ion to'qnashuv chastotasini bildiradi, $R$ plazmaning asosiy radiusi, $\epsilon$ teskari aspekt nisbati va $q$ xavfsizlik omili hisoblanadi . Plazma parametrlari $m_{\mathrm {i} }$ va $T_{\mathrm {i} }$ mos ravishda ionlarning massasi va haroratini bildiradi va $k_{\mathrm {B} }$ Boltsman doimiysi .

Elektron harorati

Harorat - bu rasmiy ta'rifi bo'lgan statistik miqdor

T=\left({\frac {\partial U}{\partial S}}\right)_{V,N},

yoki entropiyaga nisbatan ichki energiyaning o'zgarishi, ushlab turish hajmi va zarracha soni doimiy. Amaliy ta'rif tizimdagi atomlar, molekulalar yoki har qanday zarrachalar o'rtacha kinetik energiyaga ega ekanligidan kelib chiqadi. O'rtacha tizimdagi barcha zarrachalarning kinetik energiyasi bo'yicha o'rtacha degani.

Agar elektronlar guruhining tezligi, masalan, plazmadagi, Maksvell-Boltzman taqsimotiga mos keladigan bo'lsa, elektron harorati bu taqsimotning harorati sifatida aniqlanadi. Muvozanatda yoki haroratga ega bo'lmagan boshqa taqsimotlar uchun o'rtacha energiyaning uchdan ikki qismi ko'pincha harorat deb ataladi, chunki uch erkinlik darajasiga ega Maksvell-Boltzman taqsimoti uchun, $\langle E\rangle =(3/2)\,k_{\text{B}}T$ .

SI harorat birligi kelvin (K), lekin, yuqoridagi munosabatdan foydalangan holda elektron harorati ko'pincha energiya birligi elektronvolt (eV) bilan ifodalanadi. Har bir kelvin (1 K) 8,617 ga mos keladi 333 262...×10 ⁻⁵ eV; bu omil Boltsman doimiysining elementar zaryadga nisbati.^[5] Har bir eV 11605 kelvinga ekvivalent bo'lib, uni munosabat bilan hisoblash mumkin $\langle E\rangle =k_{\text{B}}T$ .

Plazmaning elektron harorati neytral turdagi yoki ionlarning haroratidan bir necha marta yuqori bo'lishi mumkin. Bu ikki faktning natijasidir. Birinchidan, ko'pgina plazma manbalari elektronlarni ionlarga qaraganda kuchliroq isitadi. Ikkinchidan, atomlar va ionlar elektronlardan ancha og'irroqdir va ikki jismning to'qnashuvida energiya uzatish massalari o'xshash bo'lsa, ancha samarali bo'ladi. Shuning uchun haroratning muvozanatlashuvi juda sekin sodir bo'ladi va kuzatish vaqt oralig'ida erishilmaydi.

Manbalar

↑ Peratt, Anthony, Physics of the Plasma Universe (1992);
↑ Parks, George K., Physics of Space Plasmas (2004, 2nd Ed.)
↑ Nucl. Fusion, Vol. 39, No. 12 (1999)
↑ Wenzel, K and Sigmar, D.. Nucl. Fusion 30, 1117 (1990)
↑ Mohr. „CODATA Energy conversion factor: Factor x for relating K to eV“. The NIST Reference on Constants, Units, and Uncertainty. National Institute of Standards and Technology (2019-yil 20-may). Qaraldi: 2019-yil 11-noyabr.

[1] Peratt, Anthony, Physics of the Plasma Universe (1992);

[2] Parks, George K., Physics of Space Plasmas (2004, 2nd Ed.)

[3] Nucl. Fusion, Vol. 39, No. 12 (1999)

[4] Wenzel, K and Sigmar, D.. Nucl. Fusion 30, 1117 (1990)

[NIST-5] Mohr. „CODATA Energy conversion factor: Factor x for relating K to eV“. The NIST Reference on Constants, Units, and Uncertainty. National Institute of Standards and Technology (2019-yil 20-may). Qaraldi: 2019-yil 11-noyabr.

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