The primary activities at Alcator C-Mod during the third quarter of FY98 were: data analysis and presentation of physics results, maintenance of the TF magnet, continued work on major systems upgrades (the RF transmitters and the Diagnostic Neutral Beam), and continued participation in the critical assessment of fusion science. A more detailed account of these activities follows.

Scientific Results

Analysis of data obtained during the most recent Alcator C-Mod run campaign was the major activity for most of the physics staff this quarter. The staff also participated in four major conferences: the `Next Step' forum, the Plasma Surface Interactions conference, the High Temperature Plasma Diagnostics conference, and the Controlled Fusion and Plasma Physics meeting of the European Physical Society. Some of the results obtained are detailed below.

Core Confinement Results

Fluctuations

Recent detailed analysis of the fast magnetic fluctuations occurring in different operational regimes shows the presence of rapidly rotating modes even when the signals are apparently incoherent. The analysis of fluctuations within sets of restricted frequency bands allows determination of perpendicular propagation speeds, even in the absence of a dominant mode. The rotation of these modes is in the electron diamagnetic (counter-I_p) direction. Since the measured propagation speed of the fluctuations is the component of velocity perpendicular to the fluctuation wavefront (and hence to B), it can also be expressed as an equivalent radial electric field that would give rise to this velocity (at the outboard midplane) through the E×B drift. Figure 1 summarizes the observed propagation speed data as a function of the parameter that it shows most systematic correlation with, the divertor neutral pressure. (Main chamber pressure is nearly proportional to the divertor pressure). The range for each measurement corresponds to the upper and lower velocity of the mode spectrum. This is not necessarily an uncertainty, since a range of velocities is certainly present. The equivalent radial fields range up to extremely large values. Radial electric fields as large as 180 kV/m have been measured on DIIID (B. Rice, et al., PRL 79 (1997) 2694), while JET and JT-60 have reported estimates of -E_r up to 60 kV/m. No systematic differences in speed can be established between ELM-Free and EDA regimes. It is also apparent from this study that the Fast Edge Modes (the `FEM' points in Fig. 1) are part of a continuum of magnetic fluctuations, occurring predominantly towards the upper end of the velocity range of the incoherent mode velocities. There is therefore no reason to regard their speeds as unusual. This supports the view that these speeds are characteristic of all plasma edge magnetic fluctuations, presumably reflecting the fluctuation convection within the edge transport barrier.

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During a run in which plasma current and toroidal field were ramped, but a steady Enhanced D_a H-mode (EDA) was maintained, magnetic fluctuations were sampled. Although the fast (1 MHz and 2 MHz) sampled magnetic pick-up coil signals were limited to 131 msec and 65 msec duration, respectively, a slowly sampled frequency comb filter array was used to measure the fluctuations in frequency bands from 56 kHz to 640 kHz. The fluctuations in the 56 to 320 kHz range all increased when ramping the current down from 1.2 MA to 0.6 MA. At higher current, the fluctuation levels were considerably lower. One detailed case of a magnetic precursor to an L-H transition was also analyzed in which a few oscillations were observed at about 100 kHz just before the transition. It appeared to be high m and n > 5 - 10 and was only visible on the outboard RF limiter coils, suggesting a high n ballooning character. The mode rotated in the electron diamagnetic drift direction. These characteristics are similar to Type III ELM precursors.

Pedestal Physics

The T_e pedestal and L-H temperature thresholds in a current scan from 0.45 to 1.4 MA were analyzed. T_e pedestals in H-mode were measured using a technique in which small ramps of B_t resulted in a few centimeter radial sweep of the position at which each ECE channel measured T_e. It was found that the T_e pedestal width did not show a simple scaling with current or r_i^pol, but increased with I_p up to 800 kA and then decreased at higher current. This indicates that other variables must be important. The best correlation of the width scaling was found to be with the pedestal height; higher pedestals had larger widths and similar T_e gradients. In contrast, the x-ray pedestal had increasing height and decreasing width as the current increased, consistent with the x-ray pedestal parameters previously measured during current ramps in a single discharge.

Temperatures just prior to the L-H transition were also analysed. T_e at the 95% poloidal flux surface showed no significant current dependence. However, the temperature gradient at this location, and T_e at locations further in the plasma, did increase (less than linearly) with I_p.

The H-mode edge pedestal shapes, as measured by various diagnostics, have been compared. T_e profiles measured by Langmuir probes, ECE, and Thomson scattering are generally consistent and show a `foot' near the separatrix and a variable width. In L-mode, ECE tends to give lower separatrix temperatures, perhaps due to lower optical depth. When the probe reaches the separatrix, a steep density profile is seen, with maximum densities reaching more than 1.5×10²⁰ m^-3, or half the average core density. X-ray pedestals are consistently 8-12 mm inside the separatrix and narrower than T_e pedestals. XUV photon emissivity profiles also steepen inside the separatrix during H-mode.

Internal Transport Barrier Evidence

Experimental evidence for the formation of an internal transport barrier during off-axis D(H) minority heating has been found. The primary evidence is a ~ 2.5-fold increase in neutron rate over the H-mode only phase with an associated 25% increase in central density. Analysis of the x-ray brightness profile also indicates a central peaking (amplitude increase by 50% and the profile width decreases by 50%). In addition, the radiation profile suggests both a core and edge barrier. As the core barrier forms, the sawtooth amplitude decreases and the sawteeth are eventually completely stabilized. This behavior is reminiscent of PEP-mode, but without pellet injection. Preliminary analysis suggests that the internal, core barrier is formed following strong ELMy phases (the neutron rate increases following two ELM bursts and a dithering L-mode phase). The radiated power profile also suggests a growing core barrier. The mode is terminated by MHD activity.

Toroidal Rotation

Professor C.S. Chang from the Courant Institute visited the group on July 9-10 in order to discuss the toroidal rotation observed on C-Mod. He presented his theory for the generation of plasma rotation by ICRH. Dr. Chang has been able to show that ICRH can induce inward radial movement of the guiding center orbits of fast minority ions without direct momentum transfer. This non-ambipolar radial transport can generate a radial electric field and subsequent plasma rotation. His theory agrees with many of the qualitative features of the C-Mod measurements. For example, the predicted toroidal rotation for C-Mod is in the same direction as the toroidal current; the direction of the rotation reverses with a reversal in the direction of toroidal current; and the rotation speeds decrease with increasing plasma current. Using H-minority tail temperatures of 30-50 keV and the predicted minority absorption power density from FPPRF and TORIC, Dr. Chang was able to predict toroidal rotation speeds in the range of V_tor = 1-3×10⁶ cm/sec and radial electric fields of ~ 100 V/cm for typical L-mode discharge parameters. Continued modelling and analysis of the C-Mod data are planned.

Density Profile Measurements

The density measurements from various main chamber diagnostics have been compared. Data from the core Thomson scattering system, the two-color interferometer, the reflectometer, and the edge reciprocating probe were compared and combined to produce the composite profile shown in Fig. 2.

Divertor and Edge Results

MARFEs, produced on the C-Mod inboard midplane, have been studied spectroscopically in order to determine their internal characteristics. We find the local density and temperature in the MARFE to be (2-3)×10²¹ m^-3 and 0.7-1.0 eV, respectively. The volume recombination rate is quite large in the MARFE, (5-10)×10²² s^-1, similar in magnitude to the plasma source rate in the core. Part of the MARFE is observed to exist inside the LCFS. Thus the recombination sink in the MARFE is a sink in confined regions of the plasma. The MARFE acts like a limiter, and ions ``recycle'' from the MARFE as neutrals. The effects of the midplane MARFE on some of the plasma parameters are shown in Fig. 3. These very high density, very cold temperature, recombining conditions have not been predicted by current MARFE models.

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Additional analysis has been performed on the total radiated power emissivity from the edge plasma at the outer midplane. A photodiode array with 2 mm radial resolution was used for these measurements. The emissivity scale-length was found to decrease from 2-3 cm to 3-4 mm after a transition from L to H-mode. Experiments where plasma current was changed during the H-mode showed a correlation between the scale-length and the plasma current. When the current was increased the scale-length decreased, and vice-versa. However, the biggest change was observed outside the separatrix. In addition, a toroidal field scan was also performed, but no change in scale-length was observed.

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Edge profiles near the outer midplane have been measured during L-mode using a new reciprocating Langmuir probe. These profile are similar to profiles measured simultaneously by the F-port reciprocating probe that scans the edge just outside the top of the divertor throat. These profiles constitute our best absolute density measurement in the edge and have also been used to calibrate the reflectometer density measurements (see above - Fig. 2).

RF Research

Part of the RF analysis effort has been directed toward understanding the effect of varying the hydrogen concentration in deuterium plasmas. One goal was to document the transition from minority to mode conversion heating in D(H) plasmas. We mixed various D/H concentrations in the gas fueling plenum in an attempt to control the hydrogen concentration in the plasma. PCX measured H/H+D ratios were 2.5%-30%. At low concentrations (H/H+D ~ 2.5%) the total central absorbed power normalized to injected power (P_abs/P_inj) was about  65% in H-mode. After increasing the measured H/H+D ratio to  10%, P_abs/P_inj increased to  85% which is in qualitative agreement with the single pass absorption minority concentration scaling. Using sawtooth reheat analysis, the central electron heating power was greatest for H/H+D ratios between 5-10%. For H/H+D ~ 15%, the central electron heating power decreased, although P_abs/P_inj remained constant within the error bars. This scaling suggests the heating power is mostly to ions at this concentration. The observed electron heating power scaling appears to be in agreement with theory although detailed study is still ongoing. At the highest concentrations, mode conversion was expected, but the experimental evidence for mode conversion is inconclusive. This result may be because of the single pass absorption density dependence. These were discharges with typical C-Mod densities, n_e^ave ~ 3×10²⁰ m^-3, which, even at the highest H/H+D ratio, means that there is poor transmission to the mode conversion layer. At the moment, the modelling is hindered by problems with the SPRUCE (RF) module in FPPRF. Dan Clark (PPPL) under the supervision of Cynthia Phillips (PPPL) is working to replace the SPRUCE module with TORIC.

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Analysis of data from the inner-wall array of RF loop probes has begun. This array is directly opposite one of the fast-wave antennas, and the loop probe signals often show a large transient when the RF is turned on. A series of three consecutive shots has been identified in which the decay time of the turn-on transient increases as the minority cyclotron resonance is moved outward from the center to the edge of the plasma. This decay is thought to be caused by heating of the bulk plasma and the generation of a minority ``tail''. Comparison is underway between those observations and the predictions of the Fokker-Planck code FPPRF.

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Paul Bonoli has been successful in modelling advanced tokamak single-null scenarios with ACCOME. He has implemented an error minimization technique which eliminated a convergence problem. (Previously, the code would begin to converge upon a solution after several iterations but then diverge.) The equilibria found after using the new error minimizations have been cross checked by Jesus Ramos using the CAXE code.

Operations and Diagnostics

In April 1998 the machine was completely disassembled for maintenance of the TF magnet. Since that time most of the technical and engineering staff have been involved in this maintenance effort.

A review of the TF magnet was held at MIT on Wednesday, May 6th. Phil Heitzenroeder and Peter Bonanos from PPPL, Phil Edmonds from U. Texas and ITER, Herb Becker from Sigmilon, and Bruce Montgomery from MTechnology were on the review committee. Presentations on the magnet, cooling system, power system, thermal and electromagnetic analysis, and proposed fault and repair scenarios were given.

A brief overview of the steps required in order to refurbish the TF sliding joints follows (those marked with an * have been completed, those marked with a + are in progress):

1

- examine the status of the sliding joints and fingers - *

2

- remove the old felt metal - *

3

- clean the finger surfaces - *

4

- design and procure an inductive heating system for soldering new felt metal pads to the fingers - *

5

- install a new 100 kW inductive heating unit for soldering - *

6

- design fixturing for the soldering procedure, including fixturing needed to position the feltmetal pads on the fingers - *

7

- silver plate the magnet fingers - +

8

- assemble a testing station capable of quantifying sliding feltmetal under a variety of temperatures, pressures, and current densities - *

9

- perform the sliding feltmetal tests - +

10

- design and implement finger diagnostics, in particular

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diagnostics of feltmetal pad pressure during machine re-assembly - *

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rogowskis on the fingers to measure the current sharing among the fingers - *

11

- machine the cracked TF core finger in preparation for repairing the crack by elctroforming - *

12

- redesign of the spring plates used to apply pressure across the finger joints and feltmetal pads - +

13

- fabricate the new spring plates

14

- solder the new feltmetal pads to the fingers using the inductive heating system - +

15

- electroform copper to seal the crack in the one of the core magnet fingers - +

16

- copper plate selected fingers to replace the copper removed during cleaning and/or grinding - +

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Progress on the DNB, the power supplies for the DNB, and on the upgrades of the RF transmitters/antennas/power delivery systems also continues. The technical details of these upgrades can be found in the weekly reports.

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Shortly after we came up-to-air at the end of the most recent run campaign, William Carmack from INEEL collected dust from the vessel with a 0.5 mm filter. Clusters of small, spherical, molybdenum particles were found along with some glass fibers associated with insulation from cabling for some of our diagnostics. A new sweep under the outer divertor modules was made, and the samples have been shipped out to INEEL.

Invessel work began by making accurate measurements of the relative position of the outer divertor modules using a gauge that was employed for this same task in 1995. Similar measurements were made at that time before the outer divertor was strengthened with solid pins and stronger mother bolts. These measurements will be compared for any changes in position. Limiter locations were also measured. The FG limiter was found to be slightly tilted left to right (2 mm). Both the FG and GH limiters have been removed so that new diagnostics can be added and old ones reworked where needed. The outer divertor module at F-port was removed from the vacuum vessel. This unit contains the embedded fast-thermocouple and the outer divertor Langmuir probe arrays. Repairs of minor damage to the probe sensors and cabling that occurred over the last two run campaigns will now proceed.

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A test fit-up of a prototype divertor `flapper' valve was performed on nine of the ten outer divertor modules. The unit was found to clear all existing in-vessel hardware including the fast-thermocouple array at F-port.

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Because the ECDC microwave system used a port which is to be used for the DNB during the next campaign, its horn has been relocated on H-port. The new vacuum interface window and coupling-horn beam line have been leak-checked, assembled, and tested for RF transmission properties. The reflected power is found to be about 5%, which is well within allowable specifications.

Collaborations and Participation in the Fusion Science Community

Martin Greenwald, Ian Hutchinson, Earl Marmar, Spencer Pitcher, Miklos Porkolab, Joe Snipes, and Steve Wolfe attended the Next Step Fusion Forum in Madison Wisconsin. Miklos Porkolab gave a presentation on ATBX, or Advanced Tokamak Burning Plasma Experiment, a reduced size, 50% cost, version of ITER. Ian Hutchinson spoke about the impact of recent discoveries on a compact ignition tokamak. Joe Snipes also presented.

A review of progress on DNB diagnostics and design of F-Port was held on May 20 at MIT. John Heard (Auburn) described the internal ECE optics. Ned Eisner (U. Texas) discussed his design for the beam limiting aperture required for MSE and BES. Norton Bretz and Bob Parsells (both of PPPL) traced recent progress on design of MSE optics. Sanjay Gangadhara described the side periscope. Bill Rowan (U. Texas) presented his design for the internal CXRS optics and the group design of F-Port flange.

Ben Carreras from Oak Ridge visited the PSFC for the weeks from July 7-21. He is working with the group on neutral particle modeling, L/H transitions, turbulent transport, and H-mode regimes. He will also be collaborating with the theory groups on various divertor problems.

A DOE Quarterly Review was held as a video-conference on July 23. Rostom Dagazian represented DOE in Gaithersburg. Randy Wilson participated, also via video link, from PPPL.

Selected Domestic Travel

In early May, Martin Greenwald travelled to Berkeley, California where he attended a DOE sponsored review of the Energy Sciences Network. At the review he made a presentation entitled ``Users Perspective: Fusion Energy Sciences''. Following the review, he attended a meeting of the ESnet Steering Committee.

May 11-15 Bob Granetz attended the ITER Disruptions and MHD Expert Group meeting in San Diego.

Miklos Porkolab attended the NSTX Dedication Ceremony at PPPL, on Monday, May 18th. He expressed the strong desire from MIT-PSFC to collaborate on this project.

John Goetz, Brian LaBombard, Bruce Lipschultz, Dimitrios Pappas, Spencer Pitcher, Jim Terry, and Maxim Umansky attended the PSI conference in San Diego, May 17-22. Five posters were presented (LaBombard, Nachtrieb, Pappas, Pitcher, and Umansky). Also three orals (Goetz, Lipschultz, W. Wampler - a Sandia collaborator) and one invited talk (Terry) were presented. The papers associated with these presentations are listed below in the ``New Publications'' section. Bruce Lipschultz attended the ITER edge database expert group meeting following PSI.

Miklos Porkolab and Earl Marmar attended the FESAC meeting on May 27th. Miklos Porkolab attended a Director's meeting with Anne Davies afterwards in Gaithersburg.

William Burke and Edward Fitzgerald were at Pillar Industries on May 28-29 for acceptance tests on the induction heating power supply.

Jim Irby attended the Enabling Technologies meeting at DOE, Germantown, May 28 and 29.

Bill Rowan (U. Texas) spent the week of May 25-29 in Austin Texas assembling DNB related optical and vacuum equipment, and directing preparatory machining on F-port horizontal flange (surface grinding, bolt holes, cowling recess).

Rejean Boivin, Jim Irby, Yijun Lin, Earl Marmar, Dmitri Mossessian, and Thomas Pedersen attended the 12th High Temperature Plasma Diagnostics Conference held June 1-5 in Princeton, New Jersey. Several posters and one invited talk were presented. The papers associated with these presentations are listed below in the ``New Publications'' section.

Martin Greenwald spent the week of June 8-12 at GA for the DIII-D 5 year review.

Miklos Porkolab attended the ``Next Step Option'' meeting at UCSD, San Diego, June 15-19 where he helped to draft the document ``ITER-Reduced Scale''. Also discussed were the Advanced Tokamak features of the Next Step.

Martin Greenwald travelled to PPPL on July 14 and 15 for a workshop on turbulence and transport. The workshop was attended by about 30 people, of which about 10 came from outside labs and the rest from PPPL. Martin presented highlights of recent transport work on C-Mod.

International Travel

Rejean Boivin, Ian Hutchinson, Miklos Porkolab, and Steve Wukitch attended the EPS Conference on Controlled Fusion and Plasma Physics, held in Prague from June 29-July 3. Ian Hutchinson presented an invited talk, Drs. Boivin and Wukitch each presented posters. Josh Stillerman and Tom Fredian attended a workshop associated with the EPS meeting, entitled ``Workshop on Remote Participation in Fusion Experiments'' and sponsored by the Remote Participation Working Group of the IAEA Fusion Power Coordinating Committee. Josh Stillerman presented an invited talk on the remote data access capabilities of the MDSplus data system.

For the week after the EPS meeting Ian Hutchinson visited JET, and Rejean Boivin was at Lausanne (TCV). Ian Hutchinson also discussed TF joints, spring plates, and feltmetal with the MAST group. Steve Wukitch visited ASDEX-Upgrade in Garching for the three weeks following the Prague meeting.

Near Term Plans

Our near term plans are focussed on finishing the repair of the TF magnet, installation of the new RF antenna, installation of the DNB and its associated diagnostics, diagnostic relocation occasioned by the antenna and DNB installations, and continued data analysis. The 1998 Alcator C-Mod Ideas Forum is scheduled for August 19-20. The forum, to be held at MIT, will consist of short (five minute) presentations proposing experiments to be carried out on Alcator C-Mod during the next run campaign. Details concerning the forum will be posted on the C-Mod Web page (http://www.psfc.mit.edu/cmod/) shortly, or can be obtained by contacting Steve Wolfe at wolfe@psfc.mit.edu. Participation in the Forum is encouraged, and mini-proposals for experiments are, as usual, being solicited from the community. (Approved MP's can be found at http://www.psfc.mit.edu/server-java/MiniProposals.)

Six papers concerning C-Mod were chosen by the US selection committee for presentation at the 1998 IAEA meeting in Yokohama, Japan. They are:

Overview of recent results for the Alcator C-Mod Tokamak, by E. Marmar

H-mode regimes in Alcator C-Mod, by M. Greenwald

Detached divertor plasmas in Alcator C-Mod: a study of the role of atomic physics,

by B. Lipschultz

Scaling of H-mode pedestal characteristics in DIII-D and C-Mod, by R. Granetz

ICRF heating experiments in Alcator C-Mod, by S. Wukitch

Modelling of advanced tokamak physics scenarios in C-Mod, by P. Bonoli

Also selected was a paper by Miklos Porkolab on ``Advanced tokamak burning plasma experiments''.

Forty-two C-Mod abstracts were submitted for the upcoming APS Division of Plasma Physics Meeting. This total includes thirteen presentations from our non-MIT collaborators. In addition, three of the C-Mod staff were selected to give invited talks at this meeting: John Goetz, on the C-Mod achievement of high core confinement with a dissipative divertor, Martin Greenwald, on C-Mod H-mode confinement regimes, and Bruce Lipshultz, on particle sources and sinks in the divertor.

T.S. Pedersen, et al., ``Edge X-Ray Imaging Measurements of plasma Edge in Alcator C-Mod'', to be published in Rev. Sci. Instrum.

D. Mossessian, et al., ``Performance of the Alcator C-Mod Thomson Scattering System'', to be published in Rev. Sci. Instrum.

J. Irby, et al., ``A Two-Color Interferometer Using a Frequency Doubled Diode Pumped laser for electron density measurements'', to be published in Rev. Sci. Instrum.

E.S. Marmar, et al., ``Visible radiation Sieve Interferometer Fluctuation Diagnostic'', to be published in Rev. Sci. Instrum.

Y. Lin, et al., ``Reflectometry Measurements of Density Profiles and Fluctuations in Alcator C-Mod'', to be published in Rev. Sci. Instrum.

J. Heard (Auburn U.), et al., ``Temperature Profile and Fluctuation Diagnostic (ECE) for Alcator C-Mod'', to be published in Rev. Sci. Instrum.

W.L. Rowan (U. Texas), et al., ``CXRS and BES for C-Mod'', to be published in Rev. Sci. Instrum.

V.A. Soukhanovskii (JHU), et al., ``FUV Spectroscopic diagnostics for radiative divertor studies at Alcator C-Mod tokamak'', to be published in Rev. Sci. Instrum.

C.F.F. Karney (PPPL), et al., ``Effect of Reflection on H_a emissions in Alcator C-Mod Tokamak'', to be published in Rev. Sci. Instrum.

D.P. Stotler (PPPL), et al., ``Spectroscopic Measurements of Hydrogen Ion temperature during divertor recombination'', to be published in Rev. Sci. Instrum.

R.J. Maqueda (LANL), et al., ``The new Infra-red Imaging system on Alcator C-Mod'', to be published in Rev. Sci. Instrum.

R. Nachtrieb, et al.,``Electron Cyclotron Discharge Cleaning (ECDC) Experiments on Alcator C-Mod'', to be published in J. Nucl. Mater.

M. Umansky, et al.,``Modeling of the Effects of Neutrals on Detachment and Edge Plasma Transport in Alcator C-Mod'', to be published in J. Nucl. Mater.

W.R. Wampler (Sandia Nat. Labs), et al., ``Molybdenum Erosion Measurements in Alcator C-Mod'', to be published in J. Nucl. Mater.

B. Lipschultz, et al., ``Recombination and Ion Loss in C-Mod Detached Divertor Discharges'', to be published in J. Nucl. Mater.

B. LaBombard, et al., ``Scrape-off Layer Impurity Transport and Screening Experiments using a Novel Tracer-Gas Injection System'', to be published in J. Nucl. Mater.

M. Umansky, et al., ``Empirical Scalings of Cross-Field Diffusivities in the Scrape-off-Layer of Alcator C-Mod from a 2-D Interpretive Model'', to be published in J. Nucl. Mater.

C.S. Pitcher, et al., ``The Roles of Friction and Recombination in SOL Pressure Balance'', to be published in J. Nucl. Mater.

J.A. Goetz, et al., ``Impurity Compression and Enrichment Studies on Alcator C-Mod'', to be published in J. Nucl. Mater.

O. Batishchev, et al., ``Kinetic Study of Thermoelectric Currents in the SOL Plasmas'', to be published in J. Nucl. Mater.

D. Pappas, et al., ``Molybdenum Sources and Sinks in the Alcator C-Mod Tokamak'', to be published in J. Nucl. Mater.

J.L. Terry, et al., ``On the Experimental Determination of the Volume Recombination Rate in Tokamak Divertors'', to be published in J. Nucl. Mater.

B. Lipschultz, et al., ``Ultrahigh Densities and Volume Recombination inside the Separatrix of the Alcator C-Mod Tokamak'', to be published in Phys. Rev. Lett.

I.H. Hutchinson, et al., ``Edge Transport Barrier Phenomena in Alcator C-Mod'', to be published in the Proc. of the 25th European Phys. Soc. Conf. on Contr. Fus. and Plasma Phys. (Prague).

S. Wukitch, et al., ``ICRH and Current Rampup Experiments in Alcator C-Mod'', to be published in the Proc. of the 25th European Phys. Soc. Conf. on Contr. Fus. and Plasma Phys. (Prague).

R.L. Boivin, et al., ``Measurements of Local and Gobal Radiated Power in Alcator C-Mod H-mode Plasmas'', to be published in the Proc. of the 25th European Phys. Soc. Conf. on Contr. Fus. and Plasma Phys. (Prague).