Jens Munk

Jens Munk
University of Alaska Anchorage | UAA · Department of Electrical Engineering

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23
Publications
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145
Citations

Publications

Publications (23)
Article
Full-text available
Ionospheric modification experiments have been performed at the High‐Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska, using a Very High Frequency (VHF) coherent scatter radar in Homer, Alaska, for experimental diagnostics. The experiments were intended to determine the threshold pump electric field required to initiate...
Article
Coherent radar backscatter spectra from auroral E region plasma irregularities can be measured with great precision and accuracy. The Doppler spectra obtained from those measurements can be used to estimate auroral convection patterns using an empirical model. These estimates are consistent with rocket, optical, and incoherent scatter radar data, b...
Article
Artificial E region field‐aligned plasma density irregularities (AFAIs) have been generated using the High‐frequency Active Auroral Research Program (HAARP) ionospheric modification facility in Gakona and observed with a 30 MHz coherent scatter radar imager in Homer, Alaska. The AFAIs were generated using a distinctive, twisted‐beam antenna pattern...
Article
Full-text available
We present a probe factor for a simple measurement device, which can be used to determine in-situ electrical resistivity in soils or other penetrable bodies. The probe is primarily sensitive to the material immediately surrounding it and therefore is ideal for determining localized conductivities. The geometry of the probe can be scaled to effectiv...
Article
This study used combined geophysical and cryostratigraphic methods for permafrost characterization in Arctic road design and engineering. Two major study areas located in the continuous permafrost zone represented a range of terrain conditions including yedoma (syngenetically frozen ice-rich silts with large ice wedges) plateaus and hills, thaw-lak...
Article
Full-text available
Woody vegetation cultivated for moisture management on evapotranspiration (ET) landfill covers could potentially serve a secondary function as a biomass crop. However, research is required to evaluate the extent to which trees could be harvested from ET covers without significantly impacting their moisture management function. This study investigat...
Article
Sporadic E ionization layers have been observed in the daytime sub-auroral ionospheric E layer by a 30-MHz radar in Alaska. The radar detects coherent backscatter from meter-scale field-aligned plasma density irregularities. The irregularities were generated by ionospheric modification — by the emission of strong HF electromagnetic waves directly b...
Article
[1] Artificial field-aligned plasma density irregularities (FAIs) were generated in the E region of the ionosphere above the High Frequency Active Auroral Research Program facility during campaigns in May and August of 2012 and observed using a 30 MHz coherent scatter radar imager in Homer, Alaska. The purpose of this ionospheric modification exper...
Article
Alternative landfill covers utilizing evapotranspiration (ET) as the primary mechanism for protecting the waste layer from aerial moisture represent promising tools for cold region solid waste management. However, ET covers have not been evaluated for use in subarctic climates. As the functionality of an ET cover is driven primarily by climactic va...
Article
Full-text available
VHF coherent scatter radar observations of an auroral substorm over Alaska are analyzed in the context of multibeam incoherent scatter plasma density and drifts data and green-line all-sky optical imagery. Coherent scatter arises from Farley Buneman waves which are excited in the E region whenever the convection electric field is greater than about...
Article
Full-text available
In order to test the efficacy ofa cold-region evapotranspiration (ET) landfill cover against a conventional compacted clay (CCL) landfill cover, two pilot scale covers were constructed in side-by-side basin lysimeters (20m x 10m x 2m) at a site in Anchorage, Alaska. The primary basis of comparison between the two lysimeters was the percolation of m...
Article
Temporal atmospheric pressure variations introduce an artifact into percolation measurements in free-draining lysimeters. This anomaly is associated with transient pressure gradients that occur as fluid and gas pressures within the lysimeter equilibrate with atmospheric pressure changes at the drain. On the basis of harmonic (Fourier) analysis of a...
Article
Electrical resistivity tomography (ERT) was utilized to evaluate soil moisture in two large (10m x 20m x 2m) basin lysimeters over a four-year period in Anchorage, Alaska. The lysimeters were intended to test the efficacy of two competing landfill cover designs, thus water balance information was collected over the entire experimental period. The f...
Article
Full-text available
An important component of ice sheet mass balance calculations is the snow accumulation rate, traditionally determined across the ice sheet from interpolated ice core data. We derive an accumulation rate map within the Greenland dry-snow facies, using C-band radar backscatter and the mean annual temperature. Values for the backscatter were obtained...
Article
Full-text available
This study examines differences in the normalized radar cross section, derived from ground-based versus spaceborne radar data. A simple homogeneous half-space model, indicates that agreement between the two improves as 1) the distance from the scatterer is increased; and/or 2) the extinction coefficient increases
Article
The cylinder is a fundamental shape for (2-D) geophysical modeling, and cylindrical objects (e.g., pipes) are a common target for ground penetrating radar. This paper presents physical and theoretical model responses for a cylinder which provide insight into responses that can be anticipated in field data. We calculate the exact expressions for the...
Conference Paper
Full-text available
The authors obtained in-situ radar backscatter data at several sites on the Greenland Ice Sheet to better relate scattering signatures to firn physical properties. Backscatter measurements were made using an ultra-wide band radar system (.5-18 GHz) for incidence angles between 0 and 50 degrees, with respect to the snow surface. For large angles of...
Article
Liquid/liquid miscibilities of four different 32 ISO VG polyolesters and one alkylbenzene at three concentrations were determined. Also a full vapor lubricant equilibrium (VLE) viscosity reduction of a 32 ISO VG mineral oil with HCFC-22 is complete. Partial viscosity reduction information by the fractionate components from R-502 in 32 ISO VG minera...
Article
A finite element solution and computer code for the electromagnetic scattering of inhomogeneous penetrable bodies is presented. The application for the code is for the analysis and design of leading and trailing edge terminations when conducting and nonconducting materials are used. Examples of simple triangular shaped terminations are also present...
Conference Paper
Two calibration approaches are examined to compare the error coefficients in signal flow models in the time domain. Ideally, the same error-coefficients should be obtained from both calibration approaches. For the most part, the calculated error coefficients are essentially the same. The only major difference occurred in the source-match term near...
Article
The focus is the determination of the electrical constitutive paramaters of materials with general complex epsilon and mu values at elevated temperatures. Measurement fixtures and techniques are evaluated for frequencies between 8 and 12 GHz using a rectangular waveguide with the sample completely filling the fixture. Three different measurement te...
Article
Liquid/liquid miscibilities of four different 32 ISO VG polyolesters and one alkylbenzene at three concentrations were determined. Also a full vapor lubricant equilibrium (VLE) viscosity reduction of a 32 ISO VG mineral oil with HCFC-22 is complete. Partial viscosity reduction information by the fractionate components from R-502 in 32 ISO VG minera...

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