## Abstract

The need for supplementary heating of magnetically confined plasmas to fusion relevant temperatures ({approx}20 keV) has been recognized from the beginning of modern fusion plasma research. Although in tokamaks the plasmas are formed initially by ohmic heating (P{Omega}{approx}{eta}{sub R}j, where j is the current density and {eta}{sub R} is the resistivity) its effectiveness deteriorates with increasing temperature since the resistivity decreases as T{sub e}{sup -3/2}, and losses due to bremsstrahlung radiation increase as Z{sub eff}{sup 3} T{sub e}{sup 1/2} (where Z{sub eff} is the effective ion charge), and the plasma current cannot be raised to arbitrarily large values because of MHD stability limits. In addition, energy losses due to thermal conduction P{sub loss} are typically anomalously large compared to neoclassical predictions and the dependence on temperature is not well understood. Thus, the simplest form of steady state power balance indicates that losses due to radiation and heat conduction must be balanced by auxiliary heating of some form, P{sub aux}, which may simply be stated as P{sub {Omega}} + P{sub {alpha}} - P{sub loss} P{sub aux} where P{sub {alpha}} is the power input provided by alpha particles, which does not become significant until the temperature exceeds some tens of keV, depending
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Porkolab, M;
Bonoli, P T;
Temkin, R J;

^{[1] }Pinsker, R I; Prater, R;^{[2] }Wilson, J R^{[3] }- Plasma Science and Fusion Center, MIT, Cambridge, MA (United States)
- General Atomics, San Diego, California (United States)
- Princeton Plasma Physics Laboratory, Princeton, NJ (United States)

## Citation Formats

Porkolab, M, Bonoli, P T, Temkin, R J, Pinsker, R I, Prater, R, and Wilson, J R.
Radiofrequency Waves, Heating and Current Drive in Magnetically Confined Plasmas.
IAEA: N. p.,
2012.
Web.

Porkolab, M, Bonoli, P T, Temkin, R J, Pinsker, R I, Prater, R, & Wilson, J R.
Radiofrequency Waves, Heating and Current Drive in Magnetically Confined Plasmas.
IAEA.

Porkolab, M, Bonoli, P T, Temkin, R J, Pinsker, R I, Prater, R, and Wilson, J R.
2012.
"Radiofrequency Waves, Heating and Current Drive in Magnetically Confined Plasmas."
IAEA.

@misc{etde_22028536,

title = {Radiofrequency Waves, Heating and Current Drive in Magnetically Confined Plasmas}

author = {Porkolab, M, Bonoli, P T, Temkin, R J, Pinsker, R I, Prater, R, and Wilson, J R}

abstractNote = {The need for supplementary heating of magnetically confined plasmas to fusion relevant temperatures ({approx}20 keV) has been recognized from the beginning of modern fusion plasma research. Although in tokamaks the plasmas are formed initially by ohmic heating (P{Omega}{approx}{eta}{sub R}j, where j is the current density and {eta}{sub R} is the resistivity) its effectiveness deteriorates with increasing temperature since the resistivity decreases as T{sub e}{sup -3/2}, and losses due to bremsstrahlung radiation increase as Z{sub eff}{sup 3} T{sub e}{sup 1/2} (where Z{sub eff} is the effective ion charge), and the plasma current cannot be raised to arbitrarily large values because of MHD stability limits. In addition, energy losses due to thermal conduction P{sub loss} are typically anomalously large compared to neoclassical predictions and the dependence on temperature is not well understood. Thus, the simplest form of steady state power balance indicates that losses due to radiation and heat conduction must be balanced by auxiliary heating of some form, P{sub aux}, which may simply be stated as P{sub {Omega}} + P{sub {alpha}} - P{sub loss} P{sub aux} where P{sub {alpha}} is the power input provided by alpha particles, which does not become significant until the temperature exceeds some tens of keV, depending on confinement and density. (author)}

place = {IAEA}

year = {2012}

month = {Sep}

}

title = {Radiofrequency Waves, Heating and Current Drive in Magnetically Confined Plasmas}

author = {Porkolab, M, Bonoli, P T, Temkin, R J, Pinsker, R I, Prater, R, and Wilson, J R}

abstractNote = {The need for supplementary heating of magnetically confined plasmas to fusion relevant temperatures ({approx}20 keV) has been recognized from the beginning of modern fusion plasma research. Although in tokamaks the plasmas are formed initially by ohmic heating (P{Omega}{approx}{eta}{sub R}j, where j is the current density and {eta}{sub R} is the resistivity) its effectiveness deteriorates with increasing temperature since the resistivity decreases as T{sub e}{sup -3/2}, and losses due to bremsstrahlung radiation increase as Z{sub eff}{sup 3} T{sub e}{sup 1/2} (where Z{sub eff} is the effective ion charge), and the plasma current cannot be raised to arbitrarily large values because of MHD stability limits. In addition, energy losses due to thermal conduction P{sub loss} are typically anomalously large compared to neoclassical predictions and the dependence on temperature is not well understood. Thus, the simplest form of steady state power balance indicates that losses due to radiation and heat conduction must be balanced by auxiliary heating of some form, P{sub aux}, which may simply be stated as P{sub {Omega}} + P{sub {alpha}} - P{sub loss} P{sub aux} where P{sub {alpha}} is the power input provided by alpha particles, which does not become significant until the temperature exceeds some tens of keV, depending on confinement and density. (author)}

place = {IAEA}

year = {2012}

month = {Sep}

}