<p>We study the electric Helmholtz equation <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\Delta u + Vu + \lambda u =f\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">Δ</mi> <mi>u</mi> <mo>+</mo> <mi>V</mi> <mi>u</mi> <mo>+</mo> <mi>λ</mi> <mi>u</mi> <mo>=</mo> <mi>f</mi> </mrow> </math></EquationSource> </InlineEquation> and show that, for certain potentials, the solution <i>u</i> given by the limited absorption principle obeys a Sommerfeld radiation condition. We use a non-spherical approach based on the solution <i>K</i> of the eikonal equation <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(|\nabla K|^2=1 + \frac{p}{\lambda }\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mrow> <mo stretchy="false">|</mo> <mi mathvariant="normal">∇</mi> <mi>K</mi> <mo stretchy="false">|</mo> </mrow> <mn>2</mn> </msup> <mo>=</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mi>p</mi> <mi>λ</mi> </mfrac> </mrow> </math></EquationSource> </InlineEquation> to improve previous results in that area and extend them to long-range potentials which decay like <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(|x|^{-2-\alpha }\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mo stretchy="false">|</mo> <mi>x</mi> <mo stretchy="false">|</mo> </mrow> <mrow> <mo>-</mo> <mn>2</mn> <mo>-</mo> <mi>α</mi> </mrow> </msup> </math></EquationSource> </InlineEquation> at infinity, with <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\alpha &gt; 0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>α</mi> <mo>&gt;</mo> <mn>0</mn> </mrow> </math></EquationSource> </InlineEquation>.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Sommerfeld Radiation Condition for Helmholtz equations with long-range potentials

  • Eric Ströher

摘要

We study the electric Helmholtz equation \(\Delta u + Vu + \lambda u =f\) Δ u + V u + λ u = f and show that, for certain potentials, the solution u given by the limited absorption principle obeys a Sommerfeld radiation condition. We use a non-spherical approach based on the solution K of the eikonal equation \(|\nabla K|^2=1 + \frac{p}{\lambda }\) | K | 2 = 1 + p λ to improve previous results in that area and extend them to long-range potentials which decay like \(|x|^{-2-\alpha }\) | x | - 2 - α at infinity, with \(\alpha > 0\) α > 0 .